The Democrats passed the ACA essentially without any Republican support. They had the power to create almost any bill they wanted. Why would anyone reasonably believe they would fix it? It is functioning exactly as designed and is enriching their donors as expected.
They really only had control for a couple of months. Abuse of the filibuster meant that they needed 60 votes in the Senate to get anything done. With Kennedy sick and Al Franken's election disputed, they didn't have 60 votes initially. After Kennedy died, the special election was won by a Republican, so they really only had 60 votes while Kennedy's interim replacement was in office. The ACA is what could be haphazardly slapped together and passed in that brief time.
