Also Hank wouldn't have been able to walk again without the treatment paid for with drug money.
I wouldn't say it is the central theme of the show but it is certainly there.
Also, both Walter and Hank's successful healing hinges on them getting the absolute top end of treatment. These don't magically become available under universal coverage. Hank is a career federal employee and must be assumed to have good insurance, but the plot explicitly places his needs outside its capabilities.
Universal health care makes sure that you don't get ruined by health expenses and that you can get patched up pretty good in the vast majority of cases. This is a good thing. But it's not a panacea that makes the top-end care that Walter and Hank receives available to the masses.