I mean, we still have more interaction with them than in the two plus decades prior to 2011 or so. Used to get literally nothing for months and months on end even between the hugely popular American Idiot and its follow up. Didn't mean they weren't still around then and it doesn't now either.
Also Billie, Mike and Tre mostly don't even use their individual instagrams for band stuff, they use it for personal things. When it comes to that you're either into doing it or you're not. If he doesn't feel like being on it it's better that he isn't. The alternative would be forcing it/only doing it to fulfill promotional obligations and that would suck anyway.