I've generally assumed that AI would make developers get lower compensation because of the lowered quantity of developers required for the same output, but this raises the possibility of it actually increasing if more developers end up doing their own things instead of entering the broader labor market :)

It could increase compensation by growing the economy. (E.g., perhaps counterintuitively, skilled immigration has this effect.)

the problem is that very few to none SWEs “doing their own thing” will ever make a penny out if it. whatever they do, if it actually makes a little traction, will be cloned and copied in a week by someone else. this whole idea that “we’ll see a 1-person billion dollar startup” is as silly as it gets