I get the idea, I think, of how silver players are supposed to be faced with choices directed at getting them to spend money or time via subbing or buying/grinding dilithium, or buying C-Store ships when they rank up. I think it's sensible.
Still, I think that the 8k per day refinement cap does its job in that regard and that dilithium should be available from more sources.
In particular, I can see why offering dilithium for first runs of missions is a bad idea: the GOAL is for silver players to be a bit short when they rank up.
However, it would all work fine and remain a tradeoff if mission REPLAY offered a dilithium ore container as one of the reward choices for missions.
Players still won't exceed 8k a day and it means foregoing the typical gear rewards from replay to get the dilithium.
It still slows things down but offers players a more entertaining way to get their dilithium.