Really? You don't see church diminishing, when church membership is at all-time lows? You don't see cafes reduced from places to have public conversation to places to do quiet, private work?
These aren't really third places, people don't show up to a mosque or church at any time of day to hang out. Maybe a church social, but that's an occasional thing and not the same as a neutral place like a coffee shop.
As a teen, the church I grew up with had a very active youth community center. There was always some group of teens hanging out there, always events going on practically every night.
At the church I'm at now there's something happening at the church at least four days a week if not more often. The playground has kids playing just about every day it's open. There are small groups of people meeting up there constantly.
Third spaces are anywhere where people can hang out that doesn’t cost money, or doesn’t cost a lot of money.
I would say that churches apply actually. And it’s not just the service itself, you have a lot of people hanging out after service in my experience. And then there is always Easter, Christmas, etc when there are snacks and everyone congregates in the basement.