East and West Germany. If that doesn't expose the horror that socialism can bring to a population I don't know how else to explain it.
If one were to make a list of all of the advances in humanity across a range of fields of study, one would be very hard pressed to match the accomplishments of capitalism-rooted systems with what came out of the entire human history of socialist-based systems. One list is a thousand kilometers long and the other, by comparison, a post-it note. I truly don't understand how anyone can defend such ideology given the overwhelming evidence against it.
The countries usually held-up as examples of "good" socialism are not socialist nations at all. The way I would characterize them is that they are capitalist nations with good to excellent social programs. And, guess, what, there's nothing wrong with that at all. But let's not call them socialism, because they are not. Socialism leads to horror and suffering. Norway, as an example, is not a socialist nation. Even better, they could not have the programs they enjoy were it not for the oil industry they intelligently use to fund aspects of their society.
Bernie and company love to grab examples like Denmark and pretend they apply one-to-one to the US. We are not Denmark and Denmark is not the US. You can't do that. You can't point at the educational system in Finland and propose we do the same in the US, it won't work. We are different, the cultures are different, it's a different reality.
The simplest examples of this is what happened in Japan during Fukushima and today in China with COVID-19. If a disaster like Fukushima or Wuhan happened in the US you would, more than likely, have looting and all kinds of criminal activity by people taking advantage of the situation. That is a cultural difference that is almost insurmountable. And so, if someone proposed bringing Japanese style policing into the US because "look at how well Fukushima worked out" they would be, well, insane, completely disconnected from reality.
That is what Sanders and company are doing with Socialism and when they compare the US to other nations. We are not the same. We are better at a few things and worse at others. We can always improve, but let's not pretend there's some magical pill that will make everything better instantly, that's not real.