What you say is true for the most part, but it does assume things like the person being able to make use of those skills.
like you stated with the snipers who were able to take out vast numbers of soldiers ... That's true, *as long as* they're able to use their training.
Consider the story of the Vietnamese sniper who would take shots at one of the camps (can't remember which one ... I believe the story is recounted by Chesty Puller in his biographies) ... The sniper would sit up in the hills and shoot GI's. Eventually, the Americans would get a lock on him (despite the sniper moving around), and wipe him out with rockets, artillery, etc). A couple weeks later, they'd get a new sniper, and the cycle would repeat.
Eventually, though, they got a sniper who seemed to be REALLY bad. Lots of nearmisses. Eventually, they cottoned on that he was missing on purpose, because, despite having the training, simply couldn't stand up to the force that was able to be directed against him. The GI's started playing along, and those going on R&R would fake getting hit, so he could report back causalities to his folk, so they didn't remove him.
Granted, it takes a severely disproportionate amount of force to dislodge someone with the training of a sniper, but it *can* be done. And someone in an urban environment is likely to have many of the things necessary for their skills to be effective negated purely by the environment -- after all, what good is being able to fade to black if you're standing under a streetlight surrounded by a gang?
|