Just wanted to add another note I believe contributes to the Overpop. Most of the maps, stock ones at least and a good number of whitelisted maps, require your squad be able to defend 2 (or more) points of entry. This boils down 2 (or more) ways for Flesh Pounds to attack the squad. And the best way to deal with a Flesh Pound is a single sharpshooter shot from a crossbow.
Now in addition to adding just one SS for every POE, you end up adding multiples of the class since each of the 5 randos that joined your game thinks THEY are a better SS for the job of keeping the team safe from FPs. In summation, because SS is the clear choice for tackling FPs (simply because no OTHER perks have any distinct advantage) you can expect an extra SS for all entry points in your holdout. Or extra multiples of them depending on your estimation of human nature.
My overarching point is that there are a lot of SSs because you "need" them. The EBR could come with 20 rounds and 4 round magazines, or deleted altogether and we'd still have an abundance of them because they are the FP class. There aren't more sharpshooter these days because they added an m14 to the game--even though that's the exact time the "problem" became evident--there's a lot of them because they can 1 shot FPs in 6 man suicidal games and if someone isn't doing that more squads wipe than should. FPs take less head damage to kill now than before the patch, they used to take 3 crossbow headshots now they take one, and SSs didn't get a triple damage boost from rank 5 to 6. Husks are more of a team Zed than FPs are now.