I think it would be a mistake to assume that dissatisfied Republican voters, or dissatisfied other conservative voters would swing back to the left...they'd be, imho, just as likely to drift further to the extreme right.
I think Liberals have a real.challenge facing them, as do the Socialists, and Socialist ~democrats..their support base appears to be shrinking to educated elites... Trying to explain to poorly educated ex workers that forces like changing technologies, the globalisation of economic activity that put them out of work won't stop and that they have to adapt, learn new skills etc, whilst being easily understood by the educated elites, is just not a message many of them will accept, too many will react emotionally, obstinately, and as Trump has demonstrated, they will buy into illogical simplistic propaganda from a Demagogue in preference to hard truths. And there are plenty of educated Conservatives willing to exploit them, eager to exploit them.