Nah, most open source UIs are really pretty bad. Most devs are horrendous designers.
Your comment about profitability is true when it comes to social media companies specifically but definitely not true for the industry as a whole. UX is a huge selling point for enterprise software and the goal there isn’t to drive clicks or views, because that’s not how those companies make money.
UX won’t be a problem as long as the maintainers are open to feedback and not stubborn about their current approach. And even if they are, an alternate front end could be introduced separate from the default one.