Okay, so I've tried on the freebie mesh jeans from Slink (mentioned above) as well as the baggy pants from Zoobong (I misremembered them as jeans). The flex of the "fabric" is seriously impressive, but I see the fitting challenge as a real potential drawback. How many people, guys in particular, are going to want to have to wear an alpha layer to keep their avatar shape from intersecting/piercing the mesh clothing? More importantly, though, at least I think so - how many guys are going to want to live with the shape imposed by a mesh item? You could well end up having to change a fair bit of your shape for a mesh clothing piece to fit properly. Areas where mesh garments meet (think about the waistline) could be a real problem, if the ingrained shapes of, say, a shirt and pants are dissimilar.
The beauty of garment-layer clothing items (such as it is) is that for the most part they "just fit". Of course we've all had to work out how to fit prim components, at least if we want that extra dimension and complexity in our wardrobe. But how many ill-fitting collars and oversize jewelry pieces do you see out there, even now?
It's a brave new world!