An end to chain rub

Chain rub usually happens when you get out of the saddle to power up a rise, or during a sprint - any time you are putting a lot of force in the cranks. Some combination of the bottom bracket axle, the cranks, the lower part of the frame and/or the wheel always had enough flex in it to result in the chain rubbing on the front derailleur.
Even my top of the line Madone 6.9SSL from circa 2011 can be made to produce a little rub once in a while.
But my two current road bikes absolutely do not, at all, ever!
Is it the gigantic volume encompassed by a modern bottom bracket in a carbon frame? I suspect it is that simple - the bike companies have made this so big, and therefore so stiff, that you can’t deflect anything associated with it enough to get even a little chain rub.

And I think that is pretty terrific.