I'm astonished anyone good photographer would even consider a "super wide
to super tele" lens. The optical challenges alone lead to some serious
compromises.

Your mindset regarding the optical challenges of high-end modern zooms
versus primes is dated. Current technology has closed any such gaps
considerably. Not to say there aren't some crappy cheap zooms out there,
but there some astonishingly good ones as well. But be prepared to pay for
the privilege of using one. These high-end zooms are designed for the pro
market, and Canon and Nikon couldn't get the money for them that they do if
they didn't deliver the results the pros demand. It certainly is reasonable
to say that you can by a tack sharp prime for considerably less money than a
zoom with comparable optical qualities, but it not reasonable to say that it
can't be done. Not today. The only compromise is to your bank account.

The convenience of composition with a zoom results in a more perfect crop
before post processing, causing less waste in resolution to the final crop.
And when you add this to the absolute magic of image stabilization and its
effective increase in speed, any slight optical advantage of the
old-fashioned prime is more than compensated for in the final result.