I'm with Karen, but slightly less scientific reasoning.
Outside of this board, how many people do you know, or have ever known, with MS? Known personally, I mean, not heard of on the grapevine?
With me, prior to diagnosis, it was precisely ONE. I've met one more since diagnosis, and become "aware of" several others (acquaintances, or friend-of-a-friend, not people well known to me). But I'm sure that's just a function of being more on the lookout for it, once you know you have it yourself.
I know my GP only has two or three other patients with MS, because she told me herself. And that's at quite a large urban practice.
So if it was really much more common than we think, wouldn't doctors be seeing it more?
How often do we see a post on here, saying: "My doctor doesn't know a thing about MS"?
How could that happen, if it was really common? It's certainly not common enough for every doctor to have dealt with it, and that is demonstrated by the alarmingly ignorant "care" some people get.
Comments like: "You wouldn't be able to walk if it was MS" spring to mind.
Shows they've never encountered it, doesn't it?