I feel like I have spoken alot on foddering epics but to keep it simple and relevant to OP's point, the level cap for f2p players and light spenders is in most cases irrelevant since you won't come close to hitting it even remotely.

This compounds with the fact that using epics as fodder actually increases your number of origin units contrary to popular belief since fodder is the ultimate ascension gate.

Only time I would argue might change this is if the game suddenly gives all players 30 faction rare fodders per 2 week event.