Yeah, I more or less agree. Sanders is an honest guy, and his heart is definitely in the right place. But as you say it's not very realistic at this point.
For example, I constantly see people posting stuff on social media about the awesomeness of the democratic socialist EU countries (Finland, Ireland, Denmark, etc). "In Denmark the minimum wage is $20 an hour and universities are free!" Well, I actually know something about these countries (I'm a dual citizen with one), and here's the point the memes always omit: the average joe in those countries pays 50% in taxes.
Not millionaires, not CEOs with yachts, but average people. Bernie says he can do it by just taxing the rich, but I don't buy it. Sweden wasn't able to sustain the welfare state by only taxing ABBA, and neither will we. Sooner or later, the kinds of programs that Bernie wants will require the average middle class American to pay much higher taxes. And at that point, he will be the most unpopular man in America.
Also, they have rather draconian immigration policies which are designed to limit the number of people who can access the welfare state. Try emigrating to Norway sometime and let me know how it goes. I assume this is not something Bernie is interested in emulating.