Free mapping doesn't 'destroy' any other online games, I'm not sure why it'd destroy LFS. In my experience most servers will still run the original maps plus a small rotation of third party maps which come to be widely accepted in the community - this is what's happened in every other game I've seen where third party mapping is possible. A consensus emerges about which third party maps are good enough to be worth using, and the community then makes them very easy to access, by putting up a compendium pack on a widely used community website or something of that nature. It's a fairly self-moderating system, really: if you put up a server with a combo that no-one chooses to race on, you'll change the combo, most likely.