You're right- there is no need for the .375 Ruger. Nor is there a need for any of the .300 or 7mm magnums. The majority of hunters in the field do not have the accuracy capability to effectively shoot big game animals past about 250 yards, or even that far away. To that range, the old .30/06 or even .308 Winchester does the job just fine and is more accurate in most hunter's hands.
: There many more calibres available than needed, only because there is a market for them and people to buy them. Of course they aren't needed, but they are wanted.
: I didn't need any more than 2 or 3 rifles for all my shooting needs, but I have them because I wanted them.
: Does anyone want a .375 Ruger? We'll see, won't we.