Anyway, relevant to the OP, doing heavy reps Olympic style is just too hard. PLUS the relative load for each individual muscle group just isn't high enough to elicit the mass gains you're after.
FOR EXAMPLE a good friend of mine who is in an Olympic sport has to do a competitive power clean (to shoulders) as an entry measure. His 1RM PB of that is around 135-140kg, whereas he does reps of deadlifts with 160-170kg (3-5 reps, so about a 85% 1RM load).
There is no way he could do multiple reps with his power clean load (try multiple heavy olympic lifts sometime), and if you consider it for the leg muscles (which provide a hell of alot of the drive and power to get the load up) as a strength training stimulus, even that isn't really at a high enough level. Do do reps of his power clean it ends up only being about 50% of his deadlift 1RM.
So, the argument of what about the upper body? Well, considering the segmental summation of motion from the leg muscles up, as much as the upper body has to work they aren't exactly having to do as much of the lifting as it seems. Sure, holding the weight at the shoulders is hard, but if you want to do that just do front squats. What if you did the press/jerk???
Well, this should make sense now...The load would have to drop even more to be able to do that as well, so relative demand for the legs reduces EVEN MORE, and then the jerk movement involves considerable leg drive as well as upper body.
Another argument is that cause you're generating so much overall force, you must be recruiting more type II fibers to do the movement. That's all well and good, but consider the overall distribution of load and relative force requirements throughout the body, and as a stimulus for hypertrophy it just doesn't make sense.
Some people are advocating power movements during the rebound/optimization phase following an acute overreaching program, but I fail to see the benefits of that compared to simply reducing volume for a period of time while maintaining high relative training intensities.