every software company i've ever worked with has an endless backlog of features it wants/needs to implement. Maybe AI just lets them move through these feature more quickly?

I mean most startups fail. And in software startups, the blame for that is usually at least shared by "software wasn't good enough". So that $20million seed investment is still going to go into "software development" - ie programmer salaries. they will be using the higher level language of ai much of the time, and be 2-5 times more efficient - but will it be enough? No. Most will still fail.