True or false most pro boxers dont pivot the foot they push off it?

[BCBUD]

The head coach who is an old old man of Irish origin says that style of fighting is very old and is not used anymore and he gave this reason why for his beef with scraps teaching is that when you push off the left quadricep with the right hamstring pulling this enables for full maximum delivery.The other issue he has is that if scraps power is coming off the back leg (falling) then you'll be off balance if that left hook misses the target, or if scrap is coming up on the balls of his feet off the uppercut then this will leave you ungrounded and open should you miss.it's hard to know if I'm understanding scrap correctly but I probably not.

On the contrary if you're leaning forward and throwing a left hook then when you miss you're gonna be wide open, if you're coming onto your back leg you'll be perfectly balanced even if you miss, and ready to throw your next shot. Coming up on the balls of the feet doesn't mean you aren't grounded, as long as you're knees and hips are engaged.

Well I think that if I can pick the back leg up then I'm not grounded! Worse is that with that style of punching your off the centre literally falling the hips are coming up.you will get it hit off the counter and lose balance and actually the punches are slower because you got a longer-range to throw.
Ask yourself this why do the best nations who produce the most champs fight off the front foot?is it because a balance here is a list of the nations which has produced the most champs.http://forums.maxboxing.com/index.php?showtopic=29979