I think the times are a changing, 30-06 and 308 used to be everywhere because they were the most popular, they are not anymore. They will make what sells fastest and the most of, which these days is pistol ammo, 223 and 6.5 somethings. I actually see quite a bit of 308 and 30-06 ammo on the shelves around here.
This is some info I found on the most popular rifle calibers.
The following list was compiled from various online and print sources, including the major ammo manufacturers' sales lists and the sales of RCBS reloading dies. The various sources tend to parallel each other, with certain exceptions. Bear in mind that a lot (probably the majority) of .223 and 7.62x39 ammo sold is for plinking or "tactical" use, not hunting. The same probably applies to a lower, but still significant, percentage of the .308 ammo sold.
"The .223, .308, .30-06, .30-30, .270, .243, 7mm Rem. Mag. and .300 Win. Mag. appear on almost all lists. The .22-250, 7.62x39mm, .300 WSM, .338 Win. Mag. and 7mm-08 Rem. have appeared on at least one list, but not others, while the .222 Remington, .30 Carbine and .303 British (once Top 10 stalwarts on most lists) have dropped back in popularity. The .300 Win. Mag. and 7mm Rem. Mag. swap places on some lists. Anyway, here are the averaged results based on the data that I could find. Consider it approximate.
USA (Averaged 2015 sales rank)
.223 Remington
.308 Winchester
.30-06 Springfield
.30-30 Winchester
.270 Winchester
.243 Winchester
7mm Remington Magnum
.300 Winchester Magnum
7.62x39mm Soviet
.22-250 Remington
End of quote
Surprised me that .22-250 is on there.
No 6.5 anythings.
You hear alot about newer "hot" cartridges but as in alot of things many people don't go out and buy what the latest and supposedly greatest is.
Most hunter have a gun they have shot for years and they keep using it. And lets be honest here, .308, .30-06 and .30-30 are all great deer rounds. If your hunting deer which is the most popular large game animal out there they are more than adequate. No need for latest and greatest 6.5 anything.
I have seen at my Local Fleet and farm some 12 and 20 ga ammo, some .223 and that been it. I haven't looked in about 2 weeks.