Personally, I'd love it if Democrats became the right-most party by staying exactly as they are, and a new party breaks off of them or evolves out to their left.

I'd say it's more likely to go the other way, with the more moderate or right-leaning Democrats breaking off to form their own party and perhaps steal away the more moderate Republican voters. There are a lot of voters who would naturally align more closely with traditional Republican political views voting Democrat only because the Republican party has been taken over by a radical faction. Having laissez-faire fiscal conservatives and outright socialists in the same party isn't really sustainable long-term; there are too many critical points of disagreement.