I guess I don't really understand the downside to bifurcation. I see it like baseball. You can use all kinds of metal or composite bats all you want until you play in a league that doesn't allow it. Like a pro league or even some amateur leagues that have such rules. Otherwise, the normal amateur, the little leaguer, the high school kid, the college player, the guy playing in an adult league....they can all use all kinds of other bats. But if you're a pro, nope. So for college players, this requires an adjustment. Well you know what? That's the price to pay for being a pro. You change equipment. Does that stop sales of these high-end metal bats at lower levels? No way. Amateurs are still trying to use the best equipment possible.
What's the downside to this? In golf, if the clubs are regulated more strictly for the pros, or in any pro event, how does that really impact guys like us that want to play? Are we really NOT going to use whatever we want just because Rory has to use a different, more highly-regulated, driver? I don't see it at all.
As for an amateur wanting to play in a pro event...the moment you step into a pro event, you gotta play by pro rules. So an amateur who normally uses a super powerful driver entering qualifying for the US Open...well, he's gotta use pro-regulated equipment at that point. That's the deal.
I honestly don't really see the issue at all.