If Obamacare had merely outlawed discrimination based on pre-existing conditions, then premiums would have gone through the roof, because lots of healthy people would have put off buying insurance until they got sick. So the law needed to include a provision requiring everyone to buy insurance. If everyone has to buy insurance, then there also have to be subsidies for people who make too much to qualify for Medicaid but not enough to afford insurance. If there are subsidies, then money to cover the cost of subsidies has to be found, through a combination of tax increases and cost savings elsewhere in the system. Those are the pillars of Obamacare; everything else is gravy.

Also, one of the sad realities of the American political system is that the only way to pass a law that pisses off some powerful interest group is to buy off other powerful interest groups at the same time.