I'm not sure what you are talking about. Gather enough LFS players, some event organizers, and you can have SC, rolling start, 1 lap qualification, etc...
Even some not-very-good VSC is possible with current InSim.
The games you mentioned are providing only a bit better/simpler support for those things (automating some of them), but you can have all of that when event organizers would put enough effort into it. I don't believe that's the major factor in the decline of active LFS players.
From the ranting on the forums in the past decade, I would rather guess it's the lack in the graphics and content, and actually I strongly suspect simple irrational "it's old 2003 game" is also quite some part of the issue, players simply move to "new" games, even if they don't provide that much more value, or the old game provides in some aspects more/better experience, but many players will simply jump on the wagon with the mainstream, which follows the "next big thing" all the time.
Actually I have strong suspicion and personal belief, that would Scawen instead of S1/S2/S3 licenses sold LFS1/2/3 games (not even changing anything on the game itself, i.e. LFS2 would be "new game" including the "LFS1" content for free, so I'm talking only about the presentation change, presenting license tiers as new games), the current early-access-LFS3 would attract more players and stir more buzz in gaming press, then mere LFS with S3 license, and constant stream of core updates (making it basically new game, when you compare the 200x version of LFS to current, but people tend to think "not much changed, it's the same game").
Anyway, after the new tyre physics, and new shaders + graphics revamp of all content, you will have basically something what Kunos did with netkar-pro (releasing it named as "AC" after the revamp, not as "patch" to Netkar, making the players to buy it as "new" game again). But LFS devs will release it as "S3 content" plus patch to the original LFS game. It's actually very nice of them, but I'm afraid the players will not recognize that value put into it.
