Why the US is the only country that ties your health insurance to your job

Because greed.

"The Affordable Care Act chose to build around it rather than abolish it."

That's a awful lot of sugarcoating... it didn't build around it, it built a pedestal for it to sit on and a cage around it to protect and reinforce it.

Insurers are laughing all the way to the bank. It's legally required that you pay enough for healthcare to not only support the medical industry but the insurance industry as well, and nothing will fix it without addressing that double cost.