There's no doubt the .375 H&H (or .375 Ruger) is the most practical choice for those hunters who want one big gun--unless, of course, they hunt really big game often enough to want an even bigger cartridge, say a .416 or .458. If I ever downsize my collection of hunting rifles to a practical minimum (which might happen if I ever "retire") my .375 H&H would probably be one that stays.
But so far I haven't given up my last .416 (a Rigby), and since buying my 9.3x62 in 2002 haven't hunted with either my .338 Winchester Magnum or .375 H&H, my two most-used "medium bores" during the 1990's. In fact, since then I've taken 14 species of big game with the 9.3x62, from impala to bull moose.