I have less than billionaires, or even the wealthy millionaires, but more than most people. What I have, I built "myself": this is to say, with much personal effort; but also with critical, non-negligible components of luck, and considerable help and work done by the right other people. My own personal work has been indispensable – but on its own, it wouldn't have been enough.
From my little perch, it seems to me that claiming one's little empire and yelling "I built all of this myself!" is nothing short of hypocrisy and egocentrism. There's no way one person builds an empire. Hundreds, or even thousands of people build it. The leadership provided by one person or several is critical, but you are not yourself building the empire. Other people are building it for you, with your partial guidance.
For there to be thousands of people who can help you build your empire, there has to be infrastructure before your business even starts. There have to be schools for your future employees to be educated. There have to be roads and telecommunications. There have to be hospitals and doctors. There has to be peace and order. There has to be a community.
Standing on top of this empire, and yelling to the world how "I built all of this myself! I want all of the rewards for me, and only me! I am an island! Any taxation is stealing!" seems to me so utterly... blind; hypocritical; narrow-minded; self-absorbed; and oblivious to other people's contributions.
So, yeah. I definitely believe that US politics would benefit a lot from moving in the direction of Sanders.
I'm originally from a high-tax European country, where taxation and bureaucracy felt oppressive. I was libertarian, and moved to Costa Rica, where I currently benefit from no taxation on foreign income. I have spent years in multiple countries where I saw the results of low taxation and low public investment. I'm now applying to move to the US, and if accepted, I expect to pay significant income tax there, in exchange for a better lifestyle, mostly due to those taxes.
I used to be libertarian before I succeeded (relatively speaking: I can't afford a jet, or anything like that). Now that I have – it seems fairly obvious how much of other people's work it takes. Not just to succeed; but to have an environment in which it is worth succeeding.