You are totally wrong.
Screwing Trumps base by not repealing Obamacare outright, will cause the base to stay home in the mid-terms, while the Trump haters turn out in record numbers. All those people in Pennsylvania and Michigan and North Carolina and Ohio who voted for the first time in decades due to Trump, will just stay home due to the treachery and backstabbing of the GOP-e.
The ONLY chance we have to keep both houses of Congress is to keep ALL of Ztrumps promises. It has only been days since Trump called on Congress to REPEAL OBAMACARE. They did not. The base will reject them for doing that and we will lose the Senate. Afterwhich any changes to Ryancare will be impossible because the Democrat Senate wont allow any.
The most current information (2015) I could find indicates that 7% of Americans buy individual health insurance coverage, and 9% have no insurance at all. This adds up to 16% of the population.
These people are the ones who are most badly screwed by ObamaCare, even if we assume that every one of the 9% with no coverage simply cannot afford an individual plan. That's only 16% of the population.
There are more people on Medicaid in this country than there are uninsured and on individual plans combined.
These Republicans in Congress are no fools. That's why they delayed the "Cadillac tax" on union insurance plans. Those union members are a bigger piece of Trump's base than those who are on individual plans.