And therefore what? The people who drafted the Constitution intended the Senate to be an aristocratic body limited to white, male, landholders. Do you think that's a good idea? How far should we go to further the intentions of the drafters? Should we revive slavery?
Here's what one guy who had to miss the Constitutional convention because he was serving his nation abroad had to say:
"I set out on this ground, which I suppose to be self evident, that the earth belongs in usufruct to the living."
(Thomas Jefferson)
And therefore if it needs updating it has always needed updating, unless something else changed. I agree with you that this is often overstressed but it is a useful perspective.