I share your enthusiasm for making it easier for people to connect in person, focused around shared interests (incl. established online social networks). I'm sincerely concerned about the potential outcomes of our current and growing social isolation.
That said, I believe that "third spaces" are still essential. Effective third spaces can provide safe, neutral ground for those who are unacquainted to get to know one another on their own terms. I think that the thought of inviting a strangers into your personal space is pretty uncomfortable to many people. I also think people want to get out of their cave every now and then--especially with the rise of work-from-home.
I think the failure of traditional third spaces (cafes, bars, social clubs, libraries, etc.) has more to do with them being unable to adapt to the needs of modern society & socialization.
My thought is that there needs to be a new type of third space which meets those needs. Perhaps something like WeWork, but geared towards the third space? Something that can adapt to and support the diverse interest/hobbies/networks that have come about due to the internet. Something that tics all of the "Great Good Place" (https://en.wikipedia.org/wiki/Third_place) boxes and more. I have some ideas, but need to develop them further.