You only have to look at the improved engine sounds we now have to see that modding can be beneficial to LFS. Personally I'd like to see more tracks but I don't want to see extensive modding like we see in other sims.
I think there could/should be a way for extra tracks to be added to the game, I think it's only a matter of working out a way to do so that fits in with what LFS is all about. I don't see how a professionally created track would need to be updated with each physics change, someone more knowledgeable on the subject may correct me on this.
Just as an idea, one possible way to do it may be to allow a very select few track builders access to the tools Eric uses for the strict purpose of creating one or a couple of tracks up to the standard necessary for official inclusion in the game. Far be it for me to volunteer them to work essentially for free but with the dedication of some members of the community I could see some people willing to do this to see something they create get into the game.
Now there could be reasons (maybe many ) I'm not aware of that would prevent my suggestion from being possible. However rather than argue about whether or not LFS should allow modding I think it's better to try to come up with ideas on how some forms of modding could be worked into the framework of LFS. Give the devs some food for thought.

Quote from tailing :

I think there could/should be a way for extra tracks to be added to the game, I think it's only a matter of working out a way to do so that fits in with what LFS is all about. I don't see how a professionally created track would need to be updated with each physics change, someone more knowledgeable on the subject may correct me on this.

I don't know what is involved with track coding or physics coding, but let's say that grip levels are changed. If this has anything to do with the track coding, then changes in grip levels cause all modded tracks to be useless and need change. Similar to improvements if we were to have dirt, oil, or debris on track. Graphic improvements, talking the graphics engine and not just textures, would cause any and all mods to be useless as well.

That's the way I am guessing it would be.

All it would take is one line of code out of the probably millions of lines of code to change and modded tracks are useless. A very simple solution..... Wait until LFS is finished, just as it's been said for 2 pages in this thread and the hundreds of other multiple page threads.

Modding won't be supported until the product is "complete", that is for sure. That doesn't mean you can't make mods, just you need to be prepared to update them with the game if you want them to keep working. It's more effort but ultimately that's the decision of the mod maker.