They didn't repeal it, because they know they'd have to replace it, and they don't have a plan to do so. After EIGHT YEARS.
They don't have a plan because they know that what their base wants would not work. What would work - an expansion of the excellent public/private Medicare / Medicare Supplement / Medicare Advantage system - would be labeled "socialism" or "Marxism" or "communism" or whatever by their base and they would lose their comfy gubmit jobs if they passed it.
So, they're fucked and look silly & incompetent as a result of partisan politics and cowardice.
.
See what I mean?