I guess the flu epidemic is just a conspiration created to distract us from the fact that nobody walked on the moon or something.
On a more serious note, what's exactly the deal with misdiagnosis? If the real thing is another virus, it could also be a virus that we should treat in a similar manner? Or the doctors are loosing precious time often with a wrong first diagnosis in a significant number of cases?
Beyond that, no, it's not likely to be a virus treated in a similar manner. If by manner you mean "drugs". Oseltamivir (aka Tamiflu) only works against influenza, so if you have RSV or some other virus, it won't do you much good. The other way to handle viral diseases is to let them run their course and manage the complications, at which point a strictly accurate diagnosis isn't particularly necessary.
TL;DR: It's very hard, fairly expensive, and the payoff per-patient isn't strong.
I just attended a talk that graphed the rate of physicians' diagnoses versus the truth, and the conclusion was that about half of physicians drastically overestimate, too (and it's far more than double, closer to five times more!).
So when 80-90% of people visiting the doctor for flu don't really have it and those doctors often make type II errors, you can hardly expect their diagnoses to be a reliable source of information.