You may want to look up the electoral history of well liked populists promising free shit in democracies around the world against the history of disliked populist fascists promising hate around the world.
Not sure I have the time to google various political elections in other countries not like the U.S. or with quite different features but in THIS country a Bernie Sanders with his limited platform of like 2-3 items with no depth and droning on and on about special interests and Wall Street with no plans or policies to discuss on immigration, health care, trade deals, foreign policy, economy, jobs, bipartisan deals.....he is just someone's old grandpa at Xmas dinner who you cannot shut up though he has a lot to say and little to do.
Realistically, with the way congress is split now, those 3 issue would take all 4 yrs. Why over promise and under deliver?
He just has a narrow focus and that is all he drones on about. Free college (paid for how?), huge taxes on Wall Street (say goodbye to great source of financing), ignoring special interests (nice idea but impossible because yo have to pass laws for someone's benefit and he will be focused on the special interests that interest him), health care reform (the only health care he should be worried about is what he will need in coming years but with the government plan he has no worries). etc... He cannot win an election pushing ideas of policies 100% for the poor and lower middle class at the expense of the rest of the people and win a popular vote/EC.