Considering that .30-06, .308, and .223 represent 85+% of the rifle caliber market, I'd have to disagree.
Any cartridge is a compromise. It will be good at some range of uses, and less good at others, and totally inappropriate for yet others. Plus, important factors like cost, widespread availability, options of bullet style & weight, reloading suitability, number and type of rifles that chamber the cartridge, and many other factors determine how well a cartridge will be received.
It sounds to me like the people you were talking to have a very narrow focus on what they believe shooting to be, and are certainly biased.
As I say over and over, before you can best choose an appropriate cartridge/rifle/pistol/shotgun/car/boat/whatever, you must first define the role(s) the item will be used for, and any other important criteria that it must meet to be acceptable (to you) for that purpose. Only then can you make an intelligent choice.
-Troy