IMHO, I think the community has very high expectations these days when it comes to simulation games, due to the advances in hardware/software technologies and the achievements of previous flight sims eg. Falcon 4
At the same time the gaming market is being dominated by the big companies, like Ubisoft and EA, which also have big interests/investment in the other genres of games, along with the mighty console game market, so they need to spread the dollars around to make the best return.
Lets face it, good flight simulators are extremely complex, require much more development time and therefor take longer to make a return. Even then the return they make may not come close to, for example, a console FPS that took half the time to develop.
Gone are the good old days of dedicated sim developers/distributors like Microprose..... ahhh, how I miss them.