This is one of the few articles where F9 makes statements not supported by any science or experiments. Cow hides are strong, but they were not built for the purpose of protecting people from road rash. I had slides on asphalt at 60 km/h in textile suits (Klim) and I am still wearing that suit as a secondary one, it got stitched back and partly cleaned and it is just fine, it just has the scars to tell the stories. In 20 years on bikes the only leather items I bought are gloves and boots; this is because this is the only option (not talking about MX/enduro boots that are mostly plastic). Never had a problem with textile equipment and never felt the need for leather. Modern Cordura and kevlar layers are fine.