When computers started they were beige boxes, now they are decorated and colorful - so we know they are done.
People worry about how phones look, so those are done.
The first smart watches were functional, now they worry more about aesthetics, but none are actually on the market. So that technology is not done, but is getting close.
Cars have been all about aesthetics for decades now.
Etc, etc.
(Don't assume "complete" means they don't improve them, it just means any further changes are minor, and mostly unimportant.)
Airplanes for example seem like they are done - but they are not sold on looks, so they are not actually done. (Maybe a little bit on the inside?)