I would say yes and no. If they had a choice between signing a striker or a grappler, they would probably sign the striker if all else was even. I don't think in the bigger picture that matters all that much though. The reason strikers are winning is because they are better than the grapplers they are fighting. Yes, there were once grapplers that would beat most of the HWs now, but that is not because the UFC is secretly hiding a bunch of HW grapplers- it's because the ones that do exist don't want to fight MMA right now; same with LHW. You can bet that if a world champ BJJ or Olympic wrestler were available, the UFC would jump all over it.