Such a simple thing as a meetup clone does not cost much to host, and is therefore immediately economically sustainable. The real concern is, as usual: is it easy to move from meetup to there, will my friends do it, etc, which depends on:

- how simple it is to register an account

- how certain are we this is not going to take the same path to profit than meetup

An example I often consider is that of bewelcome.org, that become huge after Covid when couchsurfing decided to preserve its margins by raising prices. The service is simple, non-profit, its management is open, and it's free. It mostly replaced couchsurfing, at least in the cities in europe where I used it.

Can the same be done with meetup? Maybe, I'm not sure people are frustrated by meetup as much as they were from couchsurfing, but I strongly believe that ruby-on-rail is not the distinguishing feature that will win the argument.