I have some headroom for growth set aside. Since my instance is virtualized, its not too hard to scale it a bit. But there are hard limits due to other projects on the host.
For a lot of smaller instances that are currently running on cheaper VPS instances, they most likely have an upper limit to what their willing to pay for scaling up as growth happens. The only way to balance that is getting tooling in place to purge older data, but that isn’t really a good idea either.
Really though, any web platform that hits the public eye is going to face these issues over time. But allowing a large company to federate with a smaller instance will accelerate the issues. You also need to keep in mind that you don’t have all the control of these instances, as your users will cause you to federate with more and more content. Sure, you can purge and defederate, but that is a cat and mouse game.
Also, I cannot speak for the goals of others; but lemmon bar isn’t run with the goal of replacing reddit. It is meant to be a point of access to the fediverse. No more, no less.
After being on HRT for nearly a year, the inability to satisfy the need for salt and vinegar flavored gold fishies…my poor tongue though o.O