thats a huge part of the firearms market,but the main factor is that if the manufacturers , did not constantly come out with new products to push as the latest and greatest ever designed it would take only a couple years before anyone interested in owning a firearm could have purchased one or two. and the market would be drastically reduced in size.
my dad had a 10ga ithaca double and a winchester pump 22 lr and never felt the need to buy anything else.
(always having something, being promoted as NEW,BETTER, to sell new guns)
from a pragmatic view, I think most of us could reasonably select 6-8 cartridges used for hunting and rifles that handle those 6-8 cartridges and handle almost any hunting on the planet ,
now you might not pick the same 6-8 that I would,
but if I was limited to your selection or you were limited to using my choices I doubt you would have any less success, based on the head stamps on the cases. does anyone think they would be forced to stop hunting if these were your only choices in ammo for rifle's /shotguns

example
22lr
223 rem
25/06
30/06
340 wby
378 wby
458 lott
12 ga