Physical warping of metal rotors is exceedingly rare. Instead, the pulsating pedal feeling is almost always caused by an uneven buildup of friction material—known as pad deposits or pad imprinting—baking onto the rotor surface.
Clearly you have never turned warped rotors before. It is very easy to warp brake rotors by riding the brakes constantly down hills and mountain grades. I delt with it constantly during my Automotive shop days. I never had it happen on my vehicles thanks to being a bit easier on the brakes and engine braking as needed.
As a former automotive mechanic, I most certainly have delt with "warped" rotors and have turned many a set. But they are and always have been the exception, not the rule.
Then you should know that any one that complains about warped rotors is usually riding the brakes constantly
Perhaps in the Mountains, but brake riding is not that common either except for old guys (and I'm an old guy) and ladies. Back in the '70 & '80s with single disk rotors vs ventilated rotors, more actual warping may have occurred. And back then the pad materials were way more likely to leave deposits on rotors when over heated. Todays ventilated rotors and ceramic pads, there is even less deposits when over heated. If warping is actual, it is poor installation of the wheel onto an unprepared hub or wheel surface such that the two surfaces do not lay flat on each other... again, rare.
