I feel like the biggest problem racing game eSports has is real world racing. You look at the most popular eSports games, they're almost exclusively fantasy games that offer something to viewers you can't get elsewhere. Sure if you break it down the core of some fantasy games have some basis in reality, but they still offer something viewers can't get with any real world equivalent. The only one I can think of is FIFA but two caveats there - firstly, it's the most popular sport in the world and secondly, it does have that fantasy element with fantasy teams. It still does just about offer something you can't get watching real world games.
But other than that, there is no real world Counter Strike for anyone to watch unless you can find a stream of a paintball match or something. There are no real world MOBAs. But for racing, there is. There are hundreds of real world racing series people can already watch on TV that offer the same thing the games do and SO much more.
I know personally I have no interest in watching any virtual racing events, it just doesn't interest me when it lacks so much compared to what I can already watch in the real world.
The other aspect those other games have is that viewers can usually root for a team, echoing what makes real world sports so popular. Of course there are plenty of sports with individual athletes but team sports are on the whole far more popular, so this is something else that is lacking. Of course real world motorsport has a mixture of team and single driver following but it's so much easier to learn about and relate to real world drivers than it is virtual ones.
I've never seen a compelling argument for me to tune in to any virtual race event and judging by the viewership for these events, I'm not alone. I should clarify though that I have no interest in any eSports, or online gaming at all, but still. I've tried to watch some racing events, and lost interest very quickly.
Unless virtual sim racing can start offering viewers something real world racing can't, I don't see it ever getting out of niche status in terms of eSports.