Make no mistake. San Diego devised a heck of a game plan and executed it to near perfection.
However, game plans generally work when they accentuate who you are at the core. Philip Rivers is the best 3rd down QB in the NFL (better than Manning, Rodgers, Brees, etc.). He converts those at a clip that's 15% higher than the league average. He's also been tossing short passes to his RBs for years. He's comfortable dinking and dunking all the way to the bank. Most NFL QBs will make mistakes in those situations and aren't efficient enough on 3rd down to keep their offense on the field.
San Diego ran a version of this same game plan against Denver twice (beating them in Denver during the regular season and nearly upsetting them again in the playoffs). The goal was a bit different (keep Manning off the field), but the results were nearly the same. As Pete essentially said on the radio, game plans are well and good, but at the end of the day, you need the personnel to pull it off and can't get away from who you really are. That's why I don't put much stock in other teams being able to copy what San Diego did. The game plan was tailored to their existing personality, and yet with everything going their way (including the weather), they barely squeaked this one out.