Throw out bearing

Well, man. I'm not debating it. That's not how these work. I've worked on these trucks since I was a kid doing maintenance for U-Haul. They all gain free travel when the disc wears. Every single one. In fact, my Valiant does the same thing. The only thing I've ever seen anything different on was a hydraulic or cable style clutch. Any of the old linkage style clutches I've ever worked on.....and that's a BUNCH has gained free travel as the clutch wears.
Interesting. I don't question what you have experienced. It's not the same experience I have had with clutch disc wear. It's possible the wear you experienced is coming from somewhere other than the clutch disc.