.375 is more where the medium bores end as you can load them with medium bore bullet weights and in today's market, that is more likely the majority choice.
Lots of premium bullet weights under 270 grains out there and they co-align with the .338 market more than the big bore segment.
Exactly
What John says about the bullets is correct and undoubtedly is a reflection of the widespread use of the various 375s and their velocity.
On the other hand the M70 Express rifle is 375, 416 and 458. The 378 Wby, like their 416 and 460, is not available in the lower price versions of the Mark V but the 338/378 is available. The Vanguard® Dangerous Game Rifle is 375 H&H.
Have a look at a whole lot of custom wood/blue guns and pick out all the rifles that have quarter ribs and they be pretty much all 375 and bigger. The few small caibres with a quarter rib will often be part of a pair and the other part being 375 and up.
