You’re not exactly wrong, but it’s even more fundamental than that. If leftists were a more reliable voting bloc, then Democrats couldn’t exist as they do today. They would be primaried by more leftist candidates. And then, if hard left policies were more popular with the general electorate, they would win.

The nightmare we’re all living in right now is proof. I don’t believe for an instant that The Powers That Be wanted Donald Trump to be president. Even by fascist standards he’s kind of a disaster. They wanted fucking Jeb! But Trump’s implicit message of “I’m going to fuck shit up and the establishment doesn’t want me” resonated with a lot of people. It just got the extra boost from being tied with fucked up racism, sexism, and ignorance, all of which are tied to pretty solid groups of voters.