If he manages to end the CSR payments, it will only cost the government more money in the end. Where is the master negotiator here? What kind of deal is this? Doesn't look so great to me.
It looks like he's doing it primarily for the purpose of motivating congressional democrats to revisit repeal and replace, which seems very backwards. Every single republican plan offered thus far is waaay worse than just ending the CSR payments, so democrats in congress are probably thrilled that he is openly and brazenly making health insurance worse for millions of Americans while simultaneously converting it from an Obama policy to a Trump policy. He's taking ownership of it, by deliberately and publicly making changes to the law by unilateral action. It has now become his (handicapped) baby.
This looks like the same playbook he used on DACA, the TPP, the fiduciary rule for financial advisors, the ban on civil forfeiture, the clean power plan, transgender troops, gun sales to the mentally ill, and soon on the Iran deal. He finds an existing Obama era rule that appears to be working fine, unilaterally overturns it by EO, then leaves his own republican congress scrambling to come up with some sort of replacement. Except he's doing it so fast, and congress is so dysfunctional, that nothing gets fixed even when republicans hate what he's doing.
Republicans in Congress don't really want to ruin healthcare coverage for their constituents. For the most part, they expect to be in office long after Trump is relegated to the history books as "worst US President ever." I think they mostly want to fix healthcare, but feel boxed in by their campaign rhetoric and an infantile tweeter with no grasp of policy subtleties.
Meanwhile, the president is feverishly stoking resentment among the minority of Americans who supported him in the hopes of shoring up his base, without any consideration of how his actions are impacting the country as a whole. He doesn't care about what is good for the country, only what gets applause at rallies. He's more entertainer than politician, and his impulsive pursuit of that resentful minority's applause is only weakening the country, not restoring it as he promised.