Ryan, like many conservatives, prefers to reside in an alternate universe in which the Affordable Care Act is not a budget saver but a massive drain on the federal budget (like, say, the prescription drug entitlement he supported.) The Bowles-Simpson commission examined the issue and sensibly concluded that building up the cost-saving devices in the PPACA would save money, and tearing them down would cost money. Ryan can't accept that. You can negotiate with somebody who has different preferences than you do. But negotiating with somebody who inhabits a different reality is very difficult.