I think the only point you either didn’t get from the comments or have ignored is that there are some people who are willing to pay a small price just for push notifications while self hosting, but not needing support or anything else. That’s a rational thing to ask for. There could be many smaller teams or businesses self hosting precisely because the cost of the hosted solution is high for them. They’ve already been taking care of support for their self hosted platform. Now you’re asking them to pay the same amount that they’ve been avoiding.

I hope you’d rethink on this point. Nothing else matters in this context. Not Mattermost, not Rocket Chat, not the entire open source model.