Breaking adblock even for one day likely pays the salary for several people. They would not be doing it if it didn’t pay.
You may think it’s demotivating work, but there’s a breed of engineers that lives for adversarial stuff like this.
If their progress on GPUs is anything to go by, it will take them at least a decade just to catch up to current DRAM state of the art. And it’s not like there was no incentive to build good GPUs for the last 10-15 years.
Of course they could get lucky, or could steal technologies to accelerate things, but I wouldn’t count on it happening quickly either way.
I’d imagine they have free YouTube premium.