Isn't getting 30% of every game sale / transaction (?) just because not enough? nor having ads on the consoles stores or the like, are platform owners even in charge of anything that has to do with the mp portion of a game or is it all on the devs / publishers, there is no need to think on the poor poor companies, for all we know they could be selling players info / behavior to big devs and we are paying them for that.
The infrastructure for enabling games to be played online on their console is controlled by the platform holder. That is not an easy or cheap thing to maintain when you consider these services need to be run healthily 24/7.
The developers are responsible for allocation of servers, even first party developers have to factor that into their budgets, but the actual services that these games use to connect players are run by the platform holder. That backend service that facilitates that is essentially what you're paying for.
Security, moderation, user data management, I could go on - there's a large number of workstreams involved in maintaining these services at scale. Obviously they're making plenty of profit, but the idea that it's inexpensive to run is nonsensical.
As for whether the money they make on software sales is "enough", enough means different things to different companies so you'll have to ask them lol. Ultimately, while in an ideal world they would be free to use, the money they are making is also being invested back into the service so there is still a net benefit for consumers.
And no, they are not selling your user data to developers.
Part of their 30% cut is supposed to be what covers the cost of that.
Supposed to according to who?