Fwiw, and I know this goes against the current wisdom and teaching, all but one of my 'downs' (and Ive had more than just a couple) which had slides, I was wearing jeans. The pants all had more damage than me. Even jeans are way better than no jeans; ie, riding in shorts. I did have some 'rash' and even drew some blood, but all in all did Ok, considering. Could call it luck though I have had enough experience to think there was a pattern.
The exception was with a Cordura riding pants. It had some scuffs, no real damage. Still had some rash and it seemed 'hotter' on me; the Cordura is a synthetic, jeans are cotton.
I learned early on to keep rolling, dont slide on any one spot too long. Easier said than done.....by the time you realize youre sliding you have gone a fair bit, so roll asap.....
Worst damage to one pair of jeans was the EMT cutting the leg open after the town accident that took out my knee ACL. No high tech riding pants would have changed that outcome.
I still ride in jeans, going on 50 years and over 250K miles and dont feel at risk.
YMMV, do what makes you feel safe, especially the NOT being in an accident part.