Gitlab, Discourse, Mastodon, Forem (dev.to) etc etc. All are big OSS software and are maintainable and seem to have quite a high velocity feature development. If it was an unmaintainable mess the whole opens source thing wouldn't have worked as well as it does for them. So maybe we should steer the debate towards - it CAN be done (as you can see) but it's more difficult with Rails (which I think is false).