As to what we do about it?
Nothing. We do nothing about it. I've literally watched this happen over and over and over and over since the early 90s. $Place on the internet gets popular and is then ruined by the hordes of normies and the commercialization they attract. It's even worse now with rise of influencers, troll farms, online advertising agencies, and power users.
The normie users add almost nothing to the online experience and they take so very much.
So the wisest move is to do nothing and let the flotsam and turds of the internet wash up in harbors like Reddit.
Do nothing, nothing about it. The great hordes of the unwashed have ruined every single place they've showed up starting in the early 90s. They don't want to be saved from the commercialization that has taken over the internet, to the contrary they thrive on it and are willing to put up with nearly anything to attract and keep it.
If most of Reddit shifted over to Lemmy it would get commercialized into a smoking crater. As soon as there's enough regular people using a thing the companies and venture capitalists will show up and at that point the game is over.
The best of the internet has always been built by and populated with people who don't fit into a box. It's that internet people keep trying to bring back but you can't hold the castle once it's being assaulted by the normies.
So the solution is to do nothing. Let the normies stay in their palaces of commercialization and corruption. It's for the best.