Why did M'soft develop such a thing if nobody has the money (outside of Uncle Sam) to build a system or buy the components to run it? And just for the asking, why did they ever bring Vista to the market? Nobody really likes it; there's even a move on about Saving Private XP...
I think that might be a little harsh. Sure FSX is really hardware demanding, but you don't need to spend a fortune to fly it. Most current hardware will be able to fly it, maybe not maxed out at 1920x1280, but they will be able to run the sim smoothly at lower settings. There are a lot of simmers out there on nVidia 7X00s & 8600s, or ATI 3850s, 2X00, & X1X00 series cards that can run this game and be satisfied with their performance. These are by no means top of the line cards, but they can still run the sim. Also not everyone has a Quad core CPU, but they can be happy with the look and performance in a midrange dual core. Heck, I was running it just a few months ago on a 3.0GHz p4 laptop with an ATI Mobile X300 GPU and getting very playable framerates. By setting lofty standards for FSX, microsoft can wait longer before they release the next version. Having said that though, there is nothing wrong with that strategy. You are still getting the best looking Flight Sim out right now, even on mid level settings.
As for Vista, current hardware can run Vista almost as fast as XP. If you disable much of the extra features of Vista, you will find that it runs more or less the same speed. You have to realize that XP has been around since 2001. It has been optimized and tweaked and optimized hundreds of times over those 8 years. Vista is still relatively new and hasn't had 8 years of software engineers tinkering with its performance. Many people (including myself) prefer Vista over XP. I had been running a Dual boot Visa/XP configuration for about 6 months before I switched to Vista only because I never used XP anymore.