1. Name one Russian flight sim (there have been many now) that sports a DC?
Otoh name some western flight sims that sports one. There have been quite a few other than flacon4.0. Can you count to ten. There is also one in the works.
My personal thought, this is a "cultural" thing. It could be a bit hard for western ppl to understand, maybe.

2. DC doesn't make as much money. Tis easily understood. But DC would bring more loyal fans/customers I think yes.

PS. 3. Technical difficulties... pffft yeah right. It was done even in the early 90s, I think only the DCS community puts up a mind barrier like that, for a sim that builds entirely without "dynamic" in mind, sure, it would be extremely difficult to change direction!