Federation allows for choice. Indeed, many AP implementations already add to the base AP stuff. Peertube already does this itself.
For this to really be a problem, the server software would need to be maintained by the same person running the instance, and they have to have the manpower already to either a) Build an implementation or b) Run a fork of existing software. Both take effort and quite frankly is juice that isn’t worth the squeeze to risk cutting yourself off from the network like that.