It was said that the British thought little of the first submachine guns because, as you say, we didn't need them in the last war and we don't need them in this one. It sounds like a typical conservative military attitude. But it seems to have been common in all armies. In American service, it was supposedly the Marines who took to the Thompson first.
In the case of the Springfield, I understood the reason it was adopted instead of a repeating rifle was because it was a solution to utilize all of the muzzle loading muskets that were on hand, not so much because of the cost of ammunition. But no one else was adopting a repeating rifle at the time either, though there were some that became available within the next ten or twenty years (depending on when you start counting). However, at the time, repeating rifle that were around did not take powerful ammunition but that also changed.
Usually change is forced on someone when they are on the receiving end of some weapon innovation, some of which seem trivial today, and even then, with some resistance. For instance, after the Boer War, you just had to have charger or clip loading for your infantry rifle or you where just behind the times. But some felt there was still a place for something like a magazine cut-off. Jeff Cooper even thought it was a good idea for a scout rifle.
Something that makes it more difficult to judge someone's new weapon is when you remember that there is a sort of leap frogging taking place with new weapons. The US had the M1 rifle. No one else managed to get into service a rifle of their own that was a good during the war. Both the Germans and the Soviets had semi-automatic rifles during the war but they were either not as good or not produced in large numbers. So both of them sort of skipped that form of rifle in their service. It is true that the Soviets did field the SKS but it seems to have been quickly replaced by the AK. Same cartridge, different concept of a weapon.
Given what you can do with a semi-automatic rifle, I suspect that the AK, as well as the AR-15 and even the old Stg44, would have been just as effective if they were only semi-auto.
Shoot low, sheriff. They're riding Shetlands!
Underneath the starry flag, civilize 'em with a Krag,
and return us to our own beloved homes!
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