Dear LKB, everything is in comparison as you know. If you had a winter weight silk to compare, you would know the difference. I have a couple of older winter silk editions (A la plume, Mors) - they are heavy, very substantial, don't wrinkle at all - really solid silk. IMO there is a huge difference between winter silk and summer twill once you put them side by side. I don't have that many summer silks as I got rid of most of them due to quality issues and perceived low versatiliy vs relatively high cost. I have Lalbhai, Sieste, Savana dance still, but rid of Panthera, Acinonyx and couple more. I find that Lalbhai doesn't wrinkle all that much, but Sieste does. Savana is a wash (it looks wrinkled by design) - I find the quality also very thin and cheap (alas I love how design translates into 140).
I find the same for moussies - I have vintage moussies (which are crips and don't wrinkle) while the recent editions are very thin and again wrinkle like they were chewed after one wear (and I don't even have the propensity to knot them tightly!) as compared to anything circal early 2000 or vintages.
As much as I love Animapolis design, I doubt I'd be spending $1K on that thing in summer silk
Cashmere would be worth it, but summer silk - hardly so.