That's an incorrect statement. The Young's modulus of the frame's material is irrelevant, so long as the frame is a double triangle arrangement. Any double-triangle frame made from material strong enough to be a bicycle will not flex in the vertical plane before all of the other components do -- and in fact, it won't flex vertically before several of those components deform to the point of permanent failure.
There are reasons to buy titanium frames, and reasons to carbon fiber frames, and reasons to buy aluminum frames, and so forth, but one of those reasons is not, and cannot be, rider comfort, because it is physically impossible for a double-triangle frame's material to have any effect at all on that front.
This is a simple point that everyone who buys bicycles should understand.
There is more at play than only the
in a dynamic system.
The dubious premis that comfort=vertical compliance=comfort is fallacious bordering on absurd.
This is a simple point that everyone who buys bicycles should understand.