Oh ffs are you stupid? i didnt say they pg or sp could not defeat rifles at midrange they cannot do so cost effectively. you put 2 rifles like volks or scripts against every single pg or in the case of grens or rifleman (who are more expensive but has way better dps) you simply curb stomp them simply because you have far more hp on your side for mp then the sp or pg. so the only way to be cost effective is close range and they are not suited for that.
Shocks on the other hand are more durable , cheaper (costing slightly more then a single gren) and have the tools to get close to enemy in form of smoke. because of all this you sometimes see 1vs1 games with 3 shocks. okw however uses volks + obers and ost uses pure gren spam simply because how bad sp and pg's are.
And if you disagree with simple match show me a fucking replay where you use 2-3 pg's/sp successfully.
i actually have used spios effectively against rifles but i didn't do much pushing and it was an urban map. i do not have a replay as i didn't save one and i've uninstalled the game (i'm hanging out here waiting for patch news and also for lack of anything better to do). they were also backed by a kubel which did most of the heavy managing, the spios just dealt damage. i probably would have been better off with volks but i went 3 spios because i know how boring and frustrating volks spam can be to play against; didn't build any obers either for the same reason (so edgy!).