I think it's wise to tailor our electoral strategy to the electorate we have, not the electorate we wish we had.
You're welcome to view the people who stayed home on election day as stupid - and I'm not thrilled with them, either. But the bottom line is - the squeaky wheels gets the grease, and who the squeaky wheel is has changed. Moderates used to the squeaky wheel - they could always defect to the other party, after all. They don't do that any longer - parties are very good at making their voters hate the other guy, so Rockefeller Republicans were perfectly fine with voting for Trump, if unenthused. Centrist Clinton supporters would have done the same with Bernie.
The new squeaky wheel is - not extremists, per se, but at least the disaffected. Those who have been so poorly served by the political class that they tend not to show up at all, or vote third party when they do. For Bernie, that was professional-class millenials that face a much worse future than their parents, and for Trump, that was the rural blighted white working class. If you can drive turnout among either of those, you'll be good - since it's nearly impossible to lose your moderates in the modern age of polarization.
That means that, yes, smart political parties will take your vote for granted. That puts you in essentially the same position as the extremists used to be - you will be expected to hold your nose and vote for a candidate you're not thrilled about because tactically they have the best chance of winning.