For example Czechoslovakian independent battalion in Africa didn't have sniper programme but did have capable marksmen. Likewise it didn't have artillery training but was able to crew and use captured Italian 100mm howitzers to great effect.
It was proven US armed forces DID use scoped bolt action rifles in WW1 and that they did use scoped bolt action rifles before M1903A4.
By the way, USMC sniper school was founded in 1942. What did they shoot if the US had no sniper rifles prior to 1903A4 as you insist? And Russians you seem to use so much as muster also have any official sniper schools organised centrally. Some units organised them privately and there was kinda sniper manual, but generally most of Soviet snipers were just marksmen if you insist, hardly better than US/USMC marksmen attached to squads. Many of them professional hunters - I seem to recall those of US also often had pretty good hunting background
Heck, most of the famed snipers of WWII DIDN't have any sniper school and just figured it themselves. The same goes for Japanese or Brits.
The only centralised, say official sniper schools were established by Germans and USMC. This didn't prevent "not-sniper-schoold" units to utilise scoped rifle assigned to them. And the sniping back then also wasn't usually hitting enemy at extreme ranges, but harrassing at extreme range and hitting accurately crucial enemies at combat range. It definitely didn't prvent our troops on both Western and Eastern front from employing effectively sniper rifles and selected shooters, for example sniper (or marksman, if you like) was accompanying recon patrols as a rule.
So... You have two options here. Disband snipers for anyone except Germans (yes, the Germans had legions of snipers, nobody else did) or you can rationalise that the high end sniper units just represent some really gifted shooter. The same way you have to rationalise that mortar crew can hardly hump their weapon plus 50 81mm mines, but those mines get distributed among "their" company and dumped once the mortar position is established.
As far as the game goes, I'm afraid you'll find that the high-end snipers are of little use except scenarios. Their cost is prohibitive compared to their effect.
Btw weird you don't complaint about say Brandenburgers who occupy a good space in German OOB or about the cost of Tigers or Panthers or abut unrealistically strong (number-wise) German opponent. Or Maus and Sturmtiger and all kinds of small-series stuff. All of these should be much more troubling to you as they influence game on basic settings much more than a question whether that US grunt with good shooting skills is carrying M1903A1 with Unertl scope or M1903A4 with its assigned scope.
Anyway, if you don't like US snipers, there is simple solution. Don't use them. When playing PBEM, get an agreement from your opponent that he won't buy them (he won't anyway most likely but what the...). If you think AI would ruin you by buying them, use MOBHack to set their radio code to x3 so that the AI doesn't buy them. Or if you really can't stand their existence in OOB, delete them using the same MOBHack and use your OOB set when playing PBEM.
And as far as game goes, you might notice that you're actually the only one who finds snipers to be such a crucial problem, over as long as I can remember (and I do play - and privately mod and mutilate - SPMBT and SPWW2 since SPMBT came, that's quite plenty of years already). Ad there were people *****ing about all sorts of even miniscule stuff re. reality. So it apparently for most people isn'tthat a big issue.
EDIT: And for not plying "games", what's that with you and WaW? Or that isn't a game? What it is, then?