Or spin up your own instance. Pay the $6/month it'll cost you, and never worry about ads and admins exploiting you for profit. You always have an out here.
Plus, it's not actually that expensive. Centralized services have a problem because not only do they need to cover hosting costs, but also development costs, moderating costs, and then they need to answer to shareholders and provide a return on investment. Here, everything's being done by volunteers. Development, hosting, etc. None of it is being done for profit, by businesses.
Look at it this way. If there are, say, 30k active users on the server, and hosting costs are 100 Eur/month, then it just takes 20 people donating 5 Eur/month to keep things going. And if every server has similar costs and similar benefactors, then this space is golden.
Costs, of course, will be higher over time, but there are ways to share them. Media sharing is already a thing, and if more media shares crop up, costs can be kept pretty low and people with resources and a love of community can keep things going indefinitely.
You just have to trust a small fraction of users to actually support not being the product.