No, don't host your own site. I ran the DCPHP group for years on our own site. We grew from ~10 to 400 over a span of 5 years. It was great. When I moved, the new leadership moved it to Meetup and grew from 400 to 1000 in a year. Meetup is the discovery platform for just about everyone out there. In covid times, most groups stopped meeting in person (some stopped meeting at all) but Meetup is still THE place for disc…
I'll add that as a user who wants to go to meetups, I don't want to be hassled by emails, chats, logging into a discord (that I use just to participate in this one community), and so forth. I want to look at a single app, see if any talks are of interest, click yes and add to my calendar. And because that app is already meetup, I don't want to add a second app. Its like adding a second or third chatting application.
p.s. most (not all) of the other criticism seems to be aimed at the issue of getting people to consistently meet up at all. An alternative app or messaging system would not solve this issue, and may make it worse.