There's still the corporate pressure from the host. I assume most people wouldn't be hosting Lemmy from their home for bandwidth/uptime reasons. Its hard to find a truly bulletproof VPS anymore. And they aren't cheap. With the VPS and storage you could be looking at $60-100 out of pocket.
Mine runs me around $55 a month and I have to rely on daily backups since it could be shut down with enough pressure.
Someone has to pay for this, which I imagine will be a problem eventually. I run mine for my own personal use, then I open the instances up with whatever resources I have left over. But if I was running an instance of 10,000+ users, I wouldn't be able to afford that.
It'll be a very sad day when those no longer work.