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.
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.