LFS on steam has been mentioned loads of times, I have raised it myself as well years back. The workshop in steam works great and community voting means you know which are the crap mods and which are good.
The points about the free demo raised are easily solved in that only registered used can use mods.
Would be great to see new tracks and cars and due to the way the LFS physics work I assume they would clamp stupid stuff out as you are limited to wheel base, width, engine, gearbox and the rest is just the car shell. Bit the old tool LFSTweak (or whatever it was called) allowed you to do.
I remember someone managed to inject different models into LFS via DX years back but was never released to public (Can't remember who but sure Bob will know, unless his memory is as bad as mine lol)
It could be argued mods might limit S3 sales if there are loads of cars and tracks available but again limit mods such that you have to have the highest reg level. So currently S1 users could not use mods only S2. When S3 comes out lock out S1 and S2 users from mods. Simple
The reason I stopped playing, probably true for others, is content. The games I play the most are ones where you can play something new as things remain fresh after you have explored. Oh how I would love to see Bathurst in LFS, my favorite track of all time, but that would only happen through mods
I agree one fix would at least start S3 with the VW and new track but I get the feel that S3 might be bigger than people expect if it sees the light of day. Given that the currenct tracks/models are so old I could imagine they might be in for a rework also but could be wrong.