I think comeback is a little strong.  The drubbing the alt-right took over the last few weeks in the US merely shows that the lunatic fringe is unlikely to become mainstream.

But the fissures in traditional conservatism are more complex than neo-fascist versus lower taxes and smaller government.  Social conservatism is still big in both Canada and the United States, and the fiscal conservatives are often at odds with them – abortion, same sex marriage, and transgender rights are still highly divisive both here and to the south of us.

The smart small l liberal will make hay out of those divisions, leaving small c conservatives with their core 30% and an inability to make further inroads.