i couldnt agree more
take a begginner who squats 135x15 and take his squat over the years to 400 x 15 - 20 in good form and nine times out often his legs will be much much bigger.
Hell yes.
Anytime someone tries to compare some scrawny "strong" guy to a big, "weak" guy, the point's already set sail, left harbor and is so far beyond their heads, they'd best wait for the next damn boat. It's not apples to apples; you have to compare individuals relative to their strength increases.
In addition to that, yeah, you're gonna have 20 rep squatters who move massive weights but don't have thighs to speak of. That's mostly a function of genetics, not training. Tom Platz was sure a big fan of high-rep squats (500x23, anyone?), and his wheels didn't exactly suck. Interestingly, Fred Hatfield's legs DID suck, yet he could squat more weight for a single than Tom could -- past Tom's prime, but still.
When you get into that 20 rep range, things change a little. IMO, that's as much endurance as it is strength.
A better test would be something like this ...
Show me a man who started with average lifts (struggling with, say, a 155 lb. bench and/or squat) and, over time, built up to 365 for 8-10 strict reps on the flat bench and 495 for 8-10 ass-to-grass squats. If HE didn't grow into something respectable by most any metric, I'll concede the argument.
As far as the so-called importance of a pump, I've never trained like an Olympic lifter. Do they typically get pumps in their traps, quads and delts from the singles they largely practice? If not, how come they DO typically sport great traps, delts and quads?
(One could just as easily run in the opposite direction vis-a-vis gymnasts. Again, I've never followed a gymnast through a workout, but I understand that they spend a LOT of time in the gym, day after day, year after year -- and there's no denying their upper-body development (yes, even if they are usually shredded, under a buck 50 and look far more muscular onscreen than they might if you stood shoulder-to-shoulder with one of them).)
Some people look at Olympic lifting and gymnastics to "disprove" Mentzer and company's ideas. Not so, friends ... that's a classic case of the false dilemma fallacy (a.k.a. bifurcation, a.k.a. false dichotomy, a.k.a. either/or fallacy, etc., etc.). Mentzer was all about overcompensation, and that IS something that [largely explosive] Olympic lifts, sans slow negatives, can accomplish. It's something that a dude working his butt off on parallel bars can do, even if it takes two hours for him to really kick his own ass.
At the same time, I've done some Mentzerian-style workouts, often with one or two training partners. We tried one psycho's brand of "rest-pause" lifting.
Did it result in a pump? Err ... hold that thought***. We did two sets per bodypart. After warming up with light shit, we did the full stack on the Nautilus Duo-Chest crossover. I was just a pup then, 16, so the full fucking stack was a hair much for me. OK: it was WAY too much for me. But these guys threw on the stack and made me do a rep, with their assistance.
After that, I had a 10 second rest, and thank God they lightened the weight to more like 210-220. I could budge it a few inches, then they might me fight every each 'til I got to the top -- then [very slowly] counted down from 10 as I lowered the weight.
I'll interrupt my own little tale and say that I gained sweet FUCK ALL from that kind of training. I think it was just waaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaay too stressful, even for a 16-year-old kid who wanted to be Mr. Olympia.
***Yes, that kind of lifting did result in a pump. It set in shortly after I finished lifting and lasted literally ALL g'damn day. Even the next morning, the trained areas were sore and stuff but still moderately pumped -- and believe you me, I know the difference between an actual pump and simple edema/inflammation
after I've had my boyfriend violate me so many times ... err, I mean, after I ... *sigh* Too late. The cat's out of the bag now! LOL

(I am just kidding, for the humor-impaired. But I've learned it's best 'round these parts to go ahead and at least feign some kind of faggish proclivities, then joke about them rather than say something that a closeted "fella" would be only too eager to misconstrue

.)