Stop linking medical insurance to employment via this tax bigotry. Buy it on the open market instead, or subsidize it if you're a leftist, but don't put that burden on jobs, you'll only get fewer jobs with greater hassle. People can agree to the arrangements they prefer, and it's not for us to second guess that. If there are people who end up coming up short, then you can help them yourself, or force the whole society to chip in (again, if you're a leftist), but don't force such considerations on the fragile links among private individuals and businesses.
It would be very easy to reverse, if literally anyone was willing to.
Changing the tax deduction status would harm businesses, and therefore I can't see a conservative administration ever letting that fly.
There's no reason why a law cannot be passed amending the tax code to make health insurance premiums paid by an individual tax deductible.
I'm not saying it would be easy to get such a law passed, but that doesn't change the fact that it's stupid to have health insurance tied to your employer.
(At any rate, health insurance premiums are tax deductible, but the rules are annoying and require that your healthcare spending be a certain percentage of your income.)
The origin of the practice was in WW2, when Roosevelt froze wages. To attract more and better employees, the companies threw in health insurance as a way around the restrictions.