I'll be long retired before anyone designs a working, safe, cost effective window cleaning robot.
Actually my great grandchildren will be long retired before it happens.
Every so often there's a news item about an amazing window cleaning robot, it usually turns out they cost half a million quid and require 3 engineers with PhD's to operate them.
And then also that they can only be used on buildings that are perfectly flat with no sills.
And the battery only lasts 30 minutes.
Lol!