Polls that show how right-wing American's feel about left-wing policies (but don't reveal that they are policies held by the left) result in showing that the majority of Americans are actually left-wing in regards to policy approval. Might be why Bernie Sanders is the most popular politician in America.
Polls show about half of Americans are willing to save capitalism by letting the state offer more concessions (supporting single-payer etc). And I think most people who support these things do so because it is in their own best interest, not necessarily because they want to live in an egalitarian society.
When I worked the phones here in NoVA for Sanders, only like 35% of voters we called responded favorably to Sanders' modest social democratic proposals. That's about the same % of the people that voted for him here. And Sanders isn't even that left-wing historically beyond how he labels himself.
A lot of people that did end up supporting Sanders where I live were middle-class over-educated folks who wanted their tickets to the professional class (college) to be free. Not exactly a group you'd consider leftist. It all felt very elitist at the end of the day.