Sure but Online dropped first for free so people were happy to pick it up on Steam

The campaign release was later and was included within GamePass so people made the switch then, in fact there was a large drop in Steam numbers the month after the release of Campaign likely due to people swapping over to GamePass

I'm not denying a loss in player count across all services, that absolutely has happened (and to a degree is expected to happen no game maintains the peak players) i'm saying that Steam metrics are very poor for tracking Microsoft releases

Sea of thieves has lost around 66% of average players compared to 2020 on Steam despite the fact it actually has a much larger active player count now (Though of course less than the 2021 peak)

I think it's worth mentioning the most of players of Infinite don't play it through steam but rather through gamepass on PC

The vast majority of players are also on Xbox, Steam metrics are a pretty terrible view in this instance