There can only be one answer and you know what it is before I even say anything. The Republicans in power (I dare not say establishment, CW is now going nuts when I use that word) of which John Roberts is a member in good standing, they all wanted the law. Big business and their mouthpiece the Chamber of Commerce want this law. The investment class on Wall Street, one of Barack Obama's biggest contributors want this law. They want it because the expense of providing healthcare for their workers negatively impacts their bottom line. They would rather the government do it, it's as simple as that.
Obamacare has done a lot of damage to the Democrat Party. The people spoke loud and clear in TWO elections and what they were saying was STOP THE PROGRESSIVE AGENDA! The Republicans rode this outrage to victory after victory all across the political spectrum from school boards to state houses and governorships to majorities in Congress. But as it turns out we were just platooning players in and out of the game all playing for the same team and the coach is BIG SPECIAL INTEREST. There is no doubt in my mind had the Supreme Court struck down Obamacare the Republicans would have made every effort to "fix" the law, but it would have exposed them unnecessarily as the liars and hypocrites they are, hence Robert's ruling.
Donald Trump and Bernie Sanders are perfect manifestations of this reality and what happens when a candidate goes off the reservation. I'm not saying these guys are the answer, but they sure as hell have SOMEBODY upset. The thing is we need to realize we are in a war not with Republicans or Democrats but with progressives IN BOTH PARTIES who are opposed to individual liberty, the rule of law and representative government. Do we want a new feudalism ruled by a paternalistic, top-down political hierarchy with little respect or regard for the regular folks? Of course not, and now's your chance to take the country back. I urge you to reject this multiple-choice party system where only "approved" candidates have a shot, or you could continue to support some billionaire's candidate (and that's where the real competition is, between THEIR candidates), in which case enjoy your Obamacare.