The truth is that buying a dev to rob games off other platforms doesn't "legitimize" anything. It's even more shitty than timed exclusives. But console fanboys like to peddle that tale to make themselves feel better.
Literally any dev can develop games for multiple platforms, there is no such thing as a 1st party dev. There are only devs that have been forbidden to port their games to other platforms.
Ya that’s straight up false. 1st party developer are owned by one of the Big 3. They make games as they see fit, because that’s just how business ownership works.
3rd parties aren’t owned by any console manufacturer and therefore it is in their best interest to make games for as many platforms as possible to maximize revenue. When a console manufacturer buys exclusive rights to a 3rd party game, that’s stealing a game for the masses from what is traditionally a masses developer. Being first party nullifies that.