It's astonishing how bad the US political apparatus is at making progress even on matters that easily fall within that 80%, though— healthcare reform, childcare, higher education, common sense gun laws, infrastructure investments.

All of this stuff should be a slam dunk to implement with broad coalitions no matter who holds which branches, and yet it's all been basically gridlocked for decades, and instead it's never-ending turmoil over meaningless nonsense like who uses what bathrooms.

>healthcare reform, childcare, higher education, common sense gun laws, infrastructure investments.

Funny you imagine there is consensus with any of that. The right doesn't want government healthcare. They don't want government sponsored childcare. They could care less about higher education. They want no gun laws. And they don't want black people to benefit from infrastructure.

There is no forming consensus with that position.

Its not like the US hasn't done big ambitious things before: Social Security, Medicare, Medicaid. Hell didn't they help develop some of the social programs for Post WWII Europe/Japan etc?

Post Nixon the government really just got captured and paralyzed and so a generation has grown up not understanding that this is a deliberately broken government, not how a government can operate. Instead people have been raised to think that all government is just ineffective and naturally broken. The only people who actually get it are the subset of Americans who have traveled or lived overseas for some time. As of 2023 only about half of Americans have a passport so there is a large chunk that haven't seen anything else.

A small number of extremely wealthy individuals have a vested interest in fomenting that division, because the solutions to those 80% issues happens to conflict with their business interests.