Wigwam are pretty good too
Most water resistant fabrics have a silicon or fluoropolymer hydrophobic coating. These lose their effectiveness over time, but can be reactivated to some degree by heat.
The nanosphere treatment has a very fine texture that acts as a disruptive surface and prevents dirt and water from sticking. It is designed to be longer lasting than hydrophobic coatings, but it will still wear out in time.
I've found that Schoeller Dryskin and WB-400 fabrics are really tough and abrasion resistant. They are also nicely stretchy, and don't permanently stretch out the way woven cotton does. The caveat is that they make a huge range of fabrics, so I'd guess that the lighter fabrics with finer yarn will be more delicate. The Nomad shorts look to be a lighter fabric than my unkillable MEC jacket. And like any "refined" fabric (smooth yarns, even dyeing, smooth finish), they won't age as nicely as a more irregular natural fabric. The life of the shorts will likely depend more on your tolerance for visible wear, rather than complete destruction.
If you have a tailor who will handle this kind of thing, you could probably get them to make you a pair of shorts for not much more than the Nomads. If you've got a lifter's thighs and seat, bespoke shorts will fit you way better.
My experience of dryskin is that it is tough and abrasion resistant, except against itself. There are a lot of variations on the fabric so you would need to know exactly which version it is. I had a pair of dryskin pants with the fabric containing cordura fibres. Worst pants I ever had. They pilled terribly through the crotch as the fabric was extremely abrasive against itself, but worse still they abraded anything worn against them. Wore through the hem of a softshell jacket after just a few wears.