This difference is coming from different culture and priorities. Lack of unions isn't why you don't have universal healthcare in the US and other such things. It's because the country's general culture and ideology works against both unions and social welfare.
You don't need unions to organize and demand things of the government. If people don't want to vote for social policies, unions won't make them want different things.
What about when you have bad apples in the executive team and individual employees can't remove them from the bunch? Isn't it weird and incongruous that shareholders who don't work for the company can collectively vote on and influence the makeup of the company leadership, but employees who work there cannot collectively do that? Is it supposed to be all employees working for the good of the whole, or not?
When I have to pay the 70% apple the same amount as the 100% apples, and can't really fire that apple, that's the not fair to the 100% apples.
Also I do not work at a unionized employer, my wife does as a nurse at Stanford hospital.
While I'm happy to not hate any of my current coworkers (for once!) almost every team I've been on has had some bad apples. Unions have nothing to do with that, and I'd still rather my workplace be unionized if it meant the more vulnerable members of the team were protected even if my least-favorite colleagues could exploit it for their own benefit. I've seen too many people mistreated by employers to think that unions can't be helpful.