I know things can just happen. After reading most if not all of the posts in this thread - on the face it seems that someone "rode the clutch" at some point and burned it up to point it decided to fail while you were on the beach.
I grew up at the jersey shore, when I started we did not even need permits to ride on the beach ( yes I am old ). Still have family at the jersey shore, but the outter banks of NC are our favorite beaches now. I know I am going to hear a lot of grief about this but to be honest, most of the time I drive up onto the beach without adjusting the tire pressure at all. Only during the dog days of summer ( hot august 100 degree days ) when the sand has been cooking all summer, do I lower the tire pressure. I just sold a 2004 Rubicon 5 speed manual with 145,000 miles and the original clutch. My 3 children learned how to drive on that jeep, and learned how to drive stick on that jeep. Additionally 2 girlfriends learned how to drive stick on that jeep and all five learned how to drive on the beach in that jeep and 145,000 miles later I sold the jeep with the original clutch.
Over the years a lot of people I know destroyed their clutch on the beach. On the other hand a lot of people didn't.
Best of luck !