Yeah but that's mostly network effects and free CI, which must cost them a ton of money. I'd be surprised if they're even profitable just because of that. I mean it's worth it for Microsoft clearly, but if they ever decide it isn't and turn the screws, there are at least two good alternatives - Gitlab and Codeberg.

I would also jump ship immediately if there was a platform that properly handled stacked PRs. I literally just want to be able to say "this PR includes this other PR - don't show that one". Is that too much to ask?