In the US one party promises free education, free or reduced health care to the majority of the population, etc etc.

This party is still not in power. I don't think its a foregone conclusion that people vote themselves bread and circuses, which is I think your primary point.

On another front I find it hard to believe that UBI if it ever comes to the US will be set anywhere above poverty level. In that context anyone who voted to take money from people in poverty and use it to build roads they would probably be laughed out of office and rightly so.