Yeah, although the more complex simulations have largely have largely faded away from the computer space as well. (With a few exceptions.) And very niche board games are probably more viable than very niche computer games. Modder communities for some old computer games notwithstanding.
Personally, I confess to finding complex simulations (whether of the board game or flight/combat genres) more appealing in theory than I do in practice.
They're also a pain to make. I work on complex simulations for a living, and the number of parameters and data sets you need to get good results is staggering.
If you end up just going "We think it's about 100 meters" that's a lot of effort for not much reward.
Agreed. In support of this theory, do note the tabletop world (which still exists and apparently makes money. See: Games Workshop and its many current competitors) is moving away from complex simulations, and striving to streamline and simplify the gaming experience, within reason.
For wargaming I think what happened is that “special dice and more detailed simulation” moved into “computerized simulation” (which allows a lot more depth with less player-managed overhead) in the late 1980s through the 1990s, and most of that whole end of the hobby left the tabletop world.