Really?
Ok here is some real world, non theoretical evidence.
PeterGs car, 260bhp, 300lb/ft made 260bhp at 5200 - When he went for more power it only gained a little, and went down to 4900rpm.. 1 Bar of boost - Dyno plots to prove..
Prima Racing did a customers car many moons ago, with a T3/T4, standard internals, but crude extra injectors for the fueling and played with the ignition timing at the crank sensor. It was running 25PSI!, but it made 285bhp, 300+ lbft - Again peak power made at 4900rpm - Dyno Plots to prove.
Politecnic France - Took a Lemans GTA, remapped the original ECU, ran a T3/T4 hybrid, 1.1 bar of boost, BUT did run modified cams (270 degree profile, more lift) It made 280bhp - so the cams did give them a bit of a gain - but the trade off as a mentioned before....it made peak torque at 4200rpm, and peak power at 4700rpm - and then died right off - Dyno plots to prove
Tonys A610 Engine GTA - Big turbo, bar of boost, 290 odd bhp, at around 5k? But then the manifolds glowed and collapsed.
Axel Ress - Germany. 2.5 and 3.0 GTAs, big turbos, 1.3 bar of boost, cams, circa 300bhp, with a massive car wide intercooler coming out of the rear spoiler...
Now the clincher - BVO in France took an A610 engine, 1.2 bar of boost - but put twin turbos on it, and 255 degree cams....nothing too lairy.
.....497 bhp at 6800rpm! - Dyno Plots to prove..
..and lets not forget the Safrane Biturbo - Same engine as the A610, running less boost, and makes 280bhp...
Now regardless of the accuracy of the final bhp figure - we could call it 20% either way for examples sake....all of the GTA/610 running standard manifold setup 'delivered' the power in the same way - the more power you made, the lower it got down the rev range, and was always capped off around 290bhp no matter what you do....When you see a standard car making peak power at 5750, and every tuned car making it at lower RPM - you have a restriction - and its not the cams as the Politecnic car proved - they still couldnt get past the magic 280-290 figure.
Then the moment you remove that restriction, and open up the potential, up to 200bhp more.and the power curve is excellent, linear and smooth all the way up to 7000rpm .That 610 was even running two standard 610 intercoolers sitting on the top of the engine bay, worst place for them.
Now the Politecnic car showed an increase with cams, but at lower RPM - At 5000rpm it made less power than an uncammed car, and it made peak torque 2000rpm later than an uncammed car - It had the power delivery of a turbo diesel, but without the torque delivery of a turbo diesel
...great combination...
So how much more real world evidence do you need?