It definitely depends on the place. The last large company I worked at had specialized per-technology teams. The IOS devs would be on a team with other IOS dev

It definitely depends on the place. The last large company I worked at had specialized per-technology teams. The IOS devs would be on a team with other IOS devs. Android with Android, web with web, back end with back end. My boss was seen as unusual for just trying to get different kinds of engineer on one team, even though they'd still specialize. I do think there's a difference between "this is a small team, so we all need to cross-train enough so that we don't have silos" and "we're a large company that never cleans up a mess, so you'll have to be able to work with the code from 7 different half-assed projects going each going back 1d20 years". There's no excuse for the latter, and I'm sorry you're in it.