c-fbmi nailed a very important point, the same reason why we see so few 6mm Rems, 7x57's, 8x57's (and even to an extent 6.5x55's, another great intermediate cartridge). Forty years ago they, including the Roberts, were a lot more popular when intermediate action length surplus Mausers were still state of the art action wise and cheap and plentiful. I think the little .257 'Bob has hung on quite well all considered, and the Kimbers if you're really after one aren't that hard to find, I believe Cooper offers the 'Bob as well do they not? There's the recent Ruger No.1A's as well. And in the end, if I really want a rifle, I just build it and it really doesn't matter what's off the shelf, as in the custom market everything's available including the intermediate length actions better than any production action.