The GOP was given control of the government to repeal obamacare. If they don’t they will likely lose the House, and Trump will be impeached. They don’t have a lot of time to do the repeal. If it hasn’t happened by the time announcements are made for next year’s congressional races, there will be a perception that they don’t care about the people who gave them control. That perception will doom them.
So you will rather give insane Hillary another bite of the "Destroy America" apple?
If they pitch the ACA without a reasonable and effective transition, they will lose probably terminally.
Obamacare wasn’t simply in parallel. It sucked up decades of risk investment, and destroyed it along with foundations needed to make things work.
The last chance at a relatively painless repeal was at the budget standoff several years back.
One can’t simply create a payment history and use history within a company within a brief period of time, which is at the least what you’d need for an equitable and sanely risk-balanced system to broadly work.
That said we need to move to a model where individuals own their own plans, and that it is actually insurance.