Things like 401k and healthcare are extremely complex, and that naturally means that the system is better run by a few specific people on behalf of a large number of people. Even though my healthcare is managed by my employer, it's still a remarkable pain in the ass for the parts that I have to manage myself.

That doesn't have to be the employer, but if I had to choose between putting that burden on the employer and putting it on the employee, I would put it on the employer in a heartbeat.

I think this is a better argument for why it makes sense to nationalize healthcare and relieve employers of that burden too.