This isn’t backed up by anything, but I think @Maximum_ADHD’s studio mod launcher prevents this behavior because the installer is custom. I could be wrong. As for player, I remember someone vague thread from late 2017 about how Roblox servers give up on serving you the update if you take too long to download it.
Heya! We are currently working on some improvements that should reduce the amount of data that needs to be downloaded on a client/studio update, which should help on a slower connection. Once that’s released, we can take another look and see how the process behaves at slower internet speeds.