How King v. Burwell can negate the current Healthcare landscape

It seems there's always something about Obamacare (formerly known as the Affordable Healthcare Act) that attracts detractors. This time around, the fuss is over a matter of mere words. 

An overview in brief:

King v. Burwell [formerly known as King v. Sebelius] challenges an IRS regulation imposed under the Affordable Care Act that allows subsidies on both state and federally-established health insurance exchanges. The belief, on King's side, is that the IRS regulation violates the plain language of the law enacted by Congress, which gave states the choice to either set up such exchanges themselves or stay out of the program.

An overview in videos:

What this means:

If the court rules in favor of King, then that basically negates all hope for eligibility of subsidies to people in the states without established state exchanges.

Whether it will negatively affect the people in states with already established state exchanges remains to be seen. From what I know, it doesn't seem mandatory for the states with exchanges to get rid of them if the ruling goes in favor of King, but with the mandate null and void, it doesn't seem there's much big obstacles for the state lawmakers to hurdle if they do, besides public unrest.

Speaking of public unrest, it seems there is going to be a lot of angry people over this. Those who don't have access to Obamacare anyway would essentially be slipping back into the dark ages of the old healthcare system, and there are people in the states with exchanges who can potentially lose their healthcare if the state decides to denounce exchanges (something I don't find likely). Either way, that is still millions of people who may lose their healthcare.

And with the mandate gone, one of the ACAs main goals, reducing healthcare costs, gets sacked in the process. Hypothetically speaking, the mandate was what we were supposed to bank on to reduce healthcare costs for the country. Before the ACA, the healthcare system was plagued with high costs due to the large number of uninsured people. For the consumers, it was normal for coverage to be denied resulting from preexisting conditions. Moreover, the healthy would wait until they get sick and buy insurance, indicating the existence of an adverse selection problem. Adverse selection in medical insurance markets occurs when people purchase insurance to cover known conditions. Before the mandate was a reality, the costs go up for everyone because the sick were left to buy the insurance, and as they used more insurance and filed more claims, premium rates went up, which also meant higher taxes to pay for the uninsured when they ended up needing emergency medical care. This mandate eliminates these issue, so if about 37 states cant (or won't) access that mandate, then we may end up seeing the ACA running half-fast (or half-assed).