You’re absolutely right and here’s an open source self-hosted project for MBTiles: https://github.com/akhenakh/kvtiles

More info from the author here: https://blog.nobugware.com/post/2019/self_hosted_world_maps/

The vector tiles are much smaller in filesize than pixel data and the rendering technology is much better. Almost all the styling is done on the client side so the server is basically just querying a spatial database.