Is it just me, or do replacement clutches wear out much faster than the stock clutch?

I have never had to replace an original clutch in a 200 series with less than 150,000 miles on the clock. Most have held in there for 175-200,000 miles. My '71 142E still had the original clutch at 240,000 although you could pop the clutch and the car would not stall so it was definitely worn.

The replacement clutches that I have had installed in 240's (by professional mechanics) seem to last about 75-80,000 miles. I have specified OEM parts and have asked to look at what is being installed in the car before the work begins.

Do the new discs use a different material for the lining? Is there something inherent to mating a new clutch with a resurfaced flywheel that results in a shorter clutch life?