Yes, except for Flight Sim, most of the Simulators are niche market stuff and the income isn't great. There is far more money churning out "action" games, which are all based on variations of the same simulation engine and therefore all look similar. Real low-budget production-line programming. Thank the Great Gouda that isn't the case with VStep.
I know I keep banging on about TrainSim, but although Kuju (the original developers) and Microsoft (the publishers) abandoned it many years ago, it has a huge and very active following. It has become a community supported simulator.
Even at the level where a Czech Team are continuing to patch the original Kuju bugs and develop the program.
Others (me included) produce new rolling stock, new environments, new scenery and new "missions". Most recently, I got it running without problems on Vista, even though it remains Windows 95 compatible.
But, there is in Train Simulator for commercial organisations e.g. the "Add-on pack" suppliers. They supply new environments, new trains and new "missions" for a fee. Quite good money there. Perhaps a marketing lesson for Vstep - charge for the improvements!
We need that level of following here!