I'm sure someone will flame this out, but, I'll throw out the common responses.
As pointed out, gun companies tend to market to the masses. Average guy isn't going to shoot out past 300 yards, recreationally or for hunting. Though the long range sports are exploding, finding a range beyond 200 and in most cases past 100 is kind of rare air, unless you have private property to shoot on. so what's the point?
Most hunting kills are probably less than 100 if not 50 yards, so again what's the benefit? Finding 6mm creed anything locally is a crapshoot in a lot of cases and these days even finding it on the Internet is not that easy. Your average Fudd isn't going to go for that new fangled cartridge because my 270 will kill anything on the planet out 2000 yards cause it shoots 1/4 MOA groups. If it isn't that argument then it's I don't hunt deer with anything less than a 50 BMG because they are dead right there.
From a competition standpoint, most guys shooting a 6mm will probably be a wildcat and they reload or have someone reload for them. Overall, that's not a lot of shooters in relative terms. Their investment in that caliber choice is already made, so why change what works for them.
Look outside of PRS type comps and and most Benchrest guys are shooting 6mm and they don't need the 115's. Again very small sample of overall shooter population. They don't want the 115 or 105s due to more recoil and they are all about the flat based bullets because they perform better at their 100 & 200 yard distances in theory. They never really see the benefit of a boat tail at 200 yards. As far as calibers, they are all about the BR or PPCs because it 's less powder / less cost. The 600, 1000 BR & F class may slightly change the stats, but, again relatively small pool of guns and they tend to lean on the 6.5, 7mm or 7.62 cals instead.
Next, 6mm creed has only been around since 2009, and gun industry all raved / propaganda'd the crap out of how great 6.5 was and it got all the glory as the latest greatest hottest cartridge. Now it's the 6.5 PRC or this or that. So unless you are chasing the latest greatest the propensity to move to a relatively unknown caliber is low.
Another against it argument is 6mm creed is overbore and burns barrels as faster. Then there's the why get a creed when I have a 243. Even if you go with the 243s, a considerable amount of those only shoot 50-90 grainers well due to twist rate. So no demand for the bullets. Yes some newer guns can handle them but there's not a lot of 243s with high twist rates flying off the shelves.
Availability of 6 creed at your local store probably leaves something lacking as well.
From the hunting side, yes it works, depending on game being hunted, with the right shot placement. However, a lot of guys are going to stick with heavier calibers because that's Fudded into their head. In some cases, it's just smarter and more ethical to shoot a different caliber as well.
There's been ton of change in the last 10-15 years from a technology standpoint. However, there's always a better something. Several wildcats with similar ballistics and maybe some commercial rounds as well have been around for years. I've heard Frank talk about the "if it's 10% better" on his podcast, and problem is I don't think this checks the box as a drastic improvement over what's available. I also think it was a market capture attempt by Hornady, but was was slightly more successful than the 30TC.
There's always trade offs, you just have to decided what you're willing to live with to meet your shooting goals. First rule is don't believe the hype until you gather the data yourself and prove it. Even then make sure you're being fair when you make your comparison and regurgitating some paradigm.
