I believe the Sims are expensive. Whether that is the required price to recover their production costs and make a reasonable profit. Or is it more than that price because that is what people are willing to pay.

There are a few who own more than one sim. Others who own none as they consider them too expensive.

I own one. I would like to own the major 3 (G3, AFPD, and XTR). But at $200 USD a sim. That would be too much. At $99 USD a sim I probably would.

Comments on the cost of updates is very valid too. Even updating one sim at $30 USD adds up (two expansion packs / updates = $60 USD).
It Appears Real Flight has 5 Add Ons and 2 Expansion packs. Thats $210USD on top of your initial $200USD.
There appears to be many still running G2.

I do think more people would buy them and update them if they were less expensive. The question is, would they make more money through highers sales numbers at lower prices, or continue with fewer sales and upgrades at the higher prices.