There won’t be.
Just go back to the Internet forums of old - many major forums back in the day were ran as small businesses with subscriptions and advertising. I hope the fediverse does allow a commercial model - we need diversity in how to fund such infrastructure. If some instance owners want to institute subscriptions or include advertising on their instances, that should be a feature that the Lemmy developers should seriously consider. Otherwise, it’s hard to scale a service like this on donations alone.
Some of the local subs I read have presences on Lemmy but no content. Most normies are still using Reddit.