Some people simply cannot bear the thought that there may be another hunter in the woods with a (flatter shooting, harder hitting, newer, cooler-sounding) rifle than them. I suspect that these are the same people who are satisfied driving 73 miles per hour on the freeway until someone tries to pass them at 76 miles per hour, at which point they speed up.
Some people like to get the newest, bestest, coolest thing out there as long as there is some demonstrable or perceived statistical improvement over the prior iteration of the same thing. I suspect that these are the same people who upgrade their iPhone every time a new one is released.
Some people like to give themselves, or at least appear to give themselves, every possible perceived advantage to protect against the possibility that they might...maybe...possibly...need it someday. I suspect that this is the demographic that buys 1 ton diesel pickups and chips them out, but never tow a single thing.
None of the people described above are in the wrong, they just have a different mindset than people who look at their current .308 that is no better or no worse than it was 50 years ago, and decide that it is still good enough. But gun-nut-ness provides a great platform for the people described above. Most people don't want 20 phones, and can't afford 20 pickups, and can't swap out one engine for another in the same pickup if they want to drive at sea level versus 6000 feet anyway.
But you can have 20 guns, and you can use different ammo in your rifle for coyotes than you do for moose, and that's kind of cool. But it's not for me. I suspect that when I encounter a situation where I say to myself "Boy I'd love to take that shot, but I don't think my rifle would kill the (deer, elk, antelope) so I'd better not shoot." or "Boy, I'd like to climb up on that ridge, but my rifle is just too heavy", I may change my tune. But I don't foresee either of those scenarios as likely.
By the way, I do not own a .308, but if my favorite hunting rifle was a .308 I'd be OK with that.