Anyone find that the clutch kits for sale by IPD, RPR and even the Volvo dealer just do not last as long as the factory clutch?

A little background data....The factory clutches in my 240s (I have owned 3 since 1990) have all gone 150,000+ miles. My '86 had over 180,000 on the clock when I needed to pull the clutch due to a noisy t/o bearing. The disc was well worn but had probably 20% or so of the friction material left.

I have tried Sachs and also genuine Volvo clutch kits, and find that I am lucky if the replacement clutch holds up for 100,000 mi. Average service life on the replacement parts seems to be 75,000-80,000 miles.

What's going on? Is my mechanic just not very good at installing clutch kits? Or maybe - and this is my theory - the friction material on the new discs is made from an environmentally friendly stuff that doesn't last as long under the stress of heat.