I think the wear is caused solely by dirt and grit. It gets in the gap between the tubes and, mixed with water, forms a grinding paste. Add in a dozen extensions and contractions of your pole per clean and you're doing exactly what you would do to deliberately sand down the tubes. The clamps are the worst offenders for two reasons. One, they are a tighter fit and two, they are the area where all the force is applied to the pole when you're applying any kind of turning movement. That's why they wear so much at the fully closed point.
Clean them every day and they'll last a lot longer. Clean them every week like I do and they'll last a while. Never clean them and they'll go in no time.
I've suggested one solution, which is a 1mm recess in the carbon fibre and a countersunk 1mm thick aluminium tube for the main wear points (fully closed/extended for most, on the bulges for an extreme). The problem is that it would add weight and a lot of complexity in manufacturing. I've even thought of trying to find someone to do that work to a pole; finding the right person to do it would be difficult, though.
More simply on the DIY front, I do wonder if the application of some properly strong lacquer (not the spray on stuff) at clamping points might help.
Vin
Vin