"It's actually pretty reasonable to think that as long as he is denied the White House – which still looks like the most likely outcome, though by no means inevitable – the storm will blow over with relatively little long-term change to the structure of the party."

Wrong.

The GOP and its media handmaidens recruited and developed their base.  That base nominated Donald Trump.  To think that they'll go back to supporting someone as bland as Mitt Romney, Paul Ryan, or Marco Rubio is delusional.  I'd say they've been hoisted on their own petards (if I knew what a 'petard' was).