Other sims have progressed and use latest tech. You can always find versatile content on other sims. For example AC allows modding and most mods you can find on racedepartment or their own website are rather good.
LFS still has that something about it, but it simply does not attract people anymore. You know..it's 2017 now and things are still improving along with the demand.
iRacing offers a lot more these days. Despite the ridiculous cost, if there's a chance for drivers to win a prize, there will be competition and hell that competition will be a lot higher compared to what you got in LFS now.
I am happy that there are updates coming out for LFS. It's better than nothing.