Everything will be brushless in time.  It's just the manufacturing reality that the mass scale of cordless with brushless will make it more economical to use the brushless setup in everything.

More than anything expect hybrid tools to become the norm, where they are battery tools, but you can pop the battery off and plug on the adapter to take power from the wall.  1 tools, both options.  Better for end user, cheaper for manufacture.

Brushes work, though they do wear/spark.  The biggest downside of brushless is now you have to have a micro controller in there PWMing it.  Most tools, this is a potted brick of mystery. If it fries, the tool is dead and you are replacing the whole thing since the modules aren't standardized in any way.

Some tools it dying and being replaced is just annoying and not too bad on cost. But on bigger more expensive stuff, folks want to be able to re-pair/re-build them.

If economics are the reason that Festool chooses not to use brushless motors in their cordless tools, how do you explain other companies like Makita and Milwaukee using brushless in a much wider variety of tools and selling them for less than Festool?

Give them time.  I don't know the numbers but it's safe to assume Festool is a vastly smaller company than the others.  I would guess everyone in the festool engineering/design department knows everyone in it.  Resources to do these changes aren't tiny. Especially if you tend to be a company plagued with Not Invented Here syndrome.  The parts inside most brands of tools are standard.  Items like motors are the same and or interchangeable between different brands because they get them from the same places.  Once they get set up for the new stuff, and get some unique to their tool designs worked out or a flexible architecture you can run with it and start cranking stuff out.  Add to that the mass market brands refresh the tools constantly.  I have a ton of Milwaukee tools, every time I go past them in the store tools I have look to be yet another new model, and then that changes again.  Large companies with massive sales volume makes a huge difference.   Best I know, festool doesn't change stuff much. Basic designs can be around for decades (that's not a bad thing).  So if it's not broke, you probably won't change it anytime soon. And when you do make changes, they are probably limited in how much NRE they can put towards the changes.

It would be interesting to see how much tools Festool moves in a year.  That's why there being a full US operation is a bit surprising. While in certain circles they are well know, to the general public, even people who build stuff they are a completely unknown thing.  How they stay a float based on general guesses of how many tools they probably sell a year is a mystery to me. A couple lowes and HDs in a large metro area probably sells far more saws than all of Festool USA every year.

I will say I'm surprised they don't have more brushless stuff. I had actually assumed they had far more of them when I first learned about Festool.  But still I expect it will happen over time.  It's not like I think we will see a full redesign of the TS saws and such anytime soon.  I think people are more focused on things like not having to adjust brand new tools to get things square, or improved guide rails, or making all rails "holey" is a bigger priority for folks thank the motor.

@acknowlli - The ETS EC is a corded brushless motor and so is the Planex Easy.

Quote from the Festool USA website:
The new ETS EC 150 EQ is perfectly built for manual operation to reduce fatigue when carrying out overhead sanding work and a good feeling on edges, as well as convenient operation in any position. This sander is only 4 1/2" (116 mm) high, contains a brushless EC-TEC motor, and ergonomic housing geometry with perfectly balanced center of gravity. This sander also comes with additional innovative details such as automatic dust control, integrated sanding pad brake, and the unique Vibration Control System for added health benefits.

Agreed, the Planex has the power supply/motor combination because here it makes sense for improved weight distribution (away from the head). EC makes sense here because of the dustproof design.

Regarding Mirka, yes, as I said they are slowly figuring it out. The brushless sanders had external power supplies for many years. They start getting rid of those now.

Another benefit of BL DC is high torque at low speeds. That makes sense in sanders, because the addet weight from the power supply gets compensated, because you don't need a mechanical gearbox any more.

Brushless has nothing to do with hi/lo current. hi/lo voltage.   

Brushless requires a controller, that is the difference.  It's an added cost, an if there isn't a need for it, they are not going to do it.

You design a motor for the need, if you need high torque, it will have high current draws.  Battery tools keep going to higher voltages so they can have more power without more amps.  Corded tools have never had much option, the voltage is either 120 or 230/240VAC.

There is a fundamental difference in performance between brushed and brushless motors. The brushless motor is an induction motor so if it is overloaded, by being pushed too hard, it will drop out of sync and stall.

On the other hand a brushed motor will simply draw more current and keep going, for a short time untill it overheats and burns out.

This means that, for the same user performance, a brushless motor needs to be nearly twice the wattage rating.

This doesn't mean that a BL motor will use more power. Both motors will use roughly the same power for the same job but the B motor can easily exceed its rating if required. In battery tools a BL is more efficient, and has more torque at low speed, so the battery lasts longer.

Comparing the wattage rating between B and BL motors will not give you any indication of how they will perform in a power tool in actual use.

To prevent burnout on brushed motors manufacturers fit temp sensors which, like on the TS55, shut them down until they cool down.

Brushless requires a controller, that is the difference.  It's an added cost, an if there isn't a need for it, they are not going to do it.

There is a need for it because people want it. People want quiter motors that are more controllable and run smoother. Added cost? Hmm, not sure about that. Pretty sure that controller will soon be on a single chip costing 50 cents. Of course it costs a bit more now it is still new.

I remember how I bought my first hard disk drive back in 1997. Quantum Fireball 6,4 GB, top of the line back then. Paid €200 for it. Now you can buy a 2TB SSD for only €134. It has 300 times the capacity, 1/100th the size, and works about 80-100 times faster.

  Corded tools have never had much option, the voltage is either 120 or 230/240VAC.

Not much option? My smallest 220 volt tool draws 80 watts, my biggest 2600. Try that with your 36v batteries.

Water cooled drills and cutters use an isolation transformer, so that the 230V coming out of it isn't referenced to ground, but floating. That prevents electric shock when touching a live wire while standing on conductive ground.
 
The low voltage DC power supply Mirka used for their Ceros sanders is an entirely different animal.

Interesting...I went to wet sanding at the 400 level.

From my era, I’d use 400 grit on bare steel to abrade it down to a 500/600/800 level, who knows what level it was at, all we knew was that it was more than 400 grit.

30 years ago we didn’t have the luxury of choosing a 1200/2000 grit paper, it was simply a 3M Wet or Dry 400 paper worn out sanding steel. That was the best of the best.