Voters don’t want universal healthcare. There is some lobbying, but an entire party’s voters are composed of people who only care about taxes and ensuring that those less than them do not benrfit from wealth redistribution.

This is why even the meager amount of wealth redistribution we got (which was really young to old and not wealthy to poor) came about due to a fluke 6 months in 2009 that one party had 60 senate votes, and 58 or so votes supported a taxpayer funded option, but 42 did not, so the taxpayer funded option did not make it into the final bill.

https://en.wikipedia.org/wiki/Public_health_insurance_option