Maybe Win believed that a .270 Magnum would cut into the sales of their very successful original .270?
Anybody's guess, but the widest selection of calibers gives the customers the most choices. They seemed to have a good "feel" for the desires of their consumers, commercializing the .308, developing their .243, .300 Win Mag, .358, .284, .458, .307, .225, etc. in the post-war atmosphere clear up to the mid-seventies. (My dates may be off a little, but you get the drift.) They cast a wide net for riflemen especially.
