Yeah, I'm often thankful to people building these frontends, because ultimately a lot of human information is in those corporate silos and accessing them via a frontend is better than directly.

But at the same time, I would never build such a frontend myself, for the reason you mentioned.
All it takes, is a bunch of profiteering dickwad investors, to make your efforts go poof.

its ultimately up to the whims of some evil company to waste the hundreds of hours they spent building those apps.

Or the cheapskate users who don't want to fund open source alternatives ...