I do agree that people can over decades gain more low range. It's just not as easy as the high range. Sorry that I didn't make myself clear on my comment a while ago.
I have had a number of people assert that a "real bass" can project loudly into the 1st octave with a pure chest voice, and that always seemed like an odd assertion to me, perhaps even an unhealthy goal or standard to set. That's oktavist territory, and most of the oktavists I've seen who spend real time in the 1st octave or lower are using different techniques... they rarely if ever use a coordination I could call a pure chest tone, and they typically are singing into a microphone. You have much more experience working with a wide variety of bass vocalists, so I'm curious; what are your thoughts on these kinds of assertions?