From my experience the more exotic frameworks are often pushed at smaller companies by developers hoping they'll be hard to replace whereas big companies use what s most popular to ensure they can find replacements easily.
Htmx isn't a framework, and is usually embedded in a more popular backend-rendering framework like Django or rails. Htmx is just a library that removes the need for the most common client-side SPA features, (i.e. partial page updates).
Hotwire is created by Basecamp which also houses the main creators of Rails.
Basecamp has been around for ~20 years. I have a lot of confidence that it'll be around and supported because it's a substantial part of the stack involved with a real world application that is their primary business. It's also from a group of folks who have an impeccable track record for supporting the tools they use.
