There are a couple of simple reasons why the Ruger has more going fo rit than any other .375 out there.
Basically Ruger gave the people what they wanted, and made it available.
The H&H is a great cartridge, of course. But it wasn't very available to "any man." It has stayed with us for 100 years and I don't anticipate it going away any time soon. In fact, I don't see any of the .375's dissapearing, since there are so few commercial options out there.
Weatherby came along wiht the .375 Weatherby, a great cartrdige (just like Bullcoons 375 AI

) unfortunately Weatherby dropped it in favour of the 378 Weatherby.
The .378 Weatherby is the most powerful commercial .375 cartridge available. The RUM performance is between H&H and .378 and it's not surprising that neither of them have been setting sales records, because for the most part, people don't want them or the rifles they come in.
I know Bullcoon likes to snipe moose from way the hell out there with his .375 AI but most people don't use .375"s as long range big game guns.
Weatherbys have always been pretty expensive rifles, and thier ammuntion is VERY costly. The .378 recoils pretty hard, and came with long barrels. The 375 RUM is the same way-Recoils pretty hard, expensive ammo and the barrels are long.
Most people didn't want a long range .375, since they weren't going to snipe at grizzlies, moose and buffalo at 400 yards, anyway....and with the H&H's track record for performance on large game hunting, there wasn't much desire from most hunters for the 378 and RUM. If hunters wanted more power than the H&H, they generally went up in caliber, to .416 ETC.
No, hunters wanted H&H performance in an available, affordable , fairly streamlined modern CRF rifle.
Lots of northern and Alaska guides have been carrying Mdl 70 .375 H&H and .Ruger 338 WM rifles that have been chopped to 20" barrels (look at Boomers rifle- His is the northern guides gun on steroids

) So lots of hunters wanted a sturdy, utilitarian CRF rifle, for bear and moose hunting, but also able to work as a defense gun in close quarters. Enter the Ruger Alaskan.
The other reason most peopel wanted .375 rifles was to go hunt (or dream about hunting) in Africa. The "classic" style rifle will always sell, and the Ruger African fits that bill nicely. And it sports a 23" barrel, not a cumbersome 26" barrel.
Ruger took what people wanted- about .375 H&H performance- and packaged it in 2 rifles that people wanted. And made them affordable for any hunter that really wants one. And that is why the .375 Ruger will be around for a long time, and why it has more going for it than any of the other .375's.
