It's too dangerous to build a company around open source. You're trapped between AWS eating you or having to relicense and AWS eating you. Source-available from the beginning protects you from this. The problem with OSS stuff is that people are generally price-sensitive and you can't beat the platforms for this since they get the R&D for free. It's sort of how I don't hire junior people. When others have trained them…
You could always just like, not do that? There is nothing preventing anyone from simply not open-sourcing their software. Complaining that "people can use your open source software" is like complaining about how trees split water