It is a power struggle. Rand Paul has his own bill and wants it.
Rands bill repeals the entire bill. Ryan’s doesn’t it just rearranges the deck chairs
It's much more than that. Paul wants a complete repeal, two separate bills, repeal and replace. Ryancare is not a real repeal, they just tinker around the edges.
Also, Rand does not want the new entitlement aka tax refunds. This is not a piece Ryan is willing to give up. I think Price, Pence, even Trump believe the hype that we have to cover everyone who was covered under ACA. But those who got subsidies under ACA still couldn't afford the insurance especially after high co-pays and deductibles. So why are we now trying to make sure they all come out on top at our expense?