The saying goes if you’re not the customer, you’re the product. Now, you’re both. Every big social media app is testing subscriptions. It's a business model that comes with a perverse incentive. Just like airlines, if you make life worse, more people will pay.
You’re self hosting: no qualms with that.
The most populous server is mostly full of people freeloading. They’re the same types who torrent without seeding.
It’s usually not that big a deal as long as the server has some people chipping in for upkeep but no matter how you slice it: if your account is on a server you’re either contributing to upkeep or leeching off the donations of others.
Self hosters arent leeching: they’re participating in the decentralization.
With federation servers cache content from each other and then serve it to their users. If you have a ton of users you’re using a ton of bandwidth. Simple as.