I couldn't really get into DMM cos I can't read JP and it was hindering my enjoyment, but I still log in once in a blue moon to collect all those free gems and roll some gachas.
It's not that FGs are redundant/obsolete, but that the Nutaku gold deals have been too commonplace. Which, really, is the next best thing for us, since we can't expect Nutaku to be as generous with free FGs as DMM is. That does have the side effect of intrinsically devaluing the FGs we do get, but again, it's hard to complain about it otherwise.
Cutting off the whale demand just to balance them out with the F2P'ers in a non-PVP game isn't a sound decision, anyway.