One of the issues with only following people you see in your federated time line is that you aren't growing your instance's federation. There is possible growth if you are not in the other person's federation as you might end up being introduced to their instance.

The community needs to figure out a way to aid discovery outside of the federation.

@Selsky I discover people through non-Masto sources, and through boosts from folks in my network, as well as the fed and local timelines. That seems to be keeping my feed fresh so far.
@HedgeMage I'm not saying this is a problem now. I'm meeting tons of interesting people all over the fediverse. But it might be interesting to work on those non-Masto discovery sources.