It’s an unknowable I guess.
Trump did well in a lot of traditionally democratic states simply because he wasn’t a ‘regular’ republican or democrat. Sanders may have performed similarly in traditionally republican states, given how far away from the ‘traditional democrat’ template he is.
However, Trump is a pretty strong data point that a deeper right policy slant WILL. Anyway, in a country with optional voting. winning general elections is all about getting voters from your side enthused about getting to the polls, rather than scraping off a few swinging voters from the middle.
On a related matter - the accepted ‘democrats must be moderate, polite, and bipartisan or wish alienating swinging voters’ wisdom seems bizarre in a country that just elected a guy who ran on a platform as far from moderate, polite, or bipartisan as you can get. If there’s one thing I think politicians on all sides and in all countries are starting to learn right now, it’s that the electoral price for ignorance, lies, authoritarianism, racism, and disdain for democracy is much, much lower than they had assumed. The rightwing parties to me seem to be in the vanguard of this movement right now, but I suspect all across the world, polite and conventional campaign strategic plans are increasingly lining the bins of left-wing political offices too.