Well, maybe I should have devoted a bit more thought to my decision to not renew my iRacing subscription during the Black Friday sale. Or not. It's hard to say.
The reason for my recent reconsideration of the issue comes from the first update of 2018. The big news in this update is the introduction of Rallycross. If you aren't aware of what that is, just imagine a traditional paved race track with a mid-lap detour into a dirt motocross track. A race like this would obviously need a specially designed car that's able to perform adequately in either mode. With that in mind, you can see the appeal to iRacing: sell more cars.
They do provide a VW beetle as a "free" car, and there is also a Ford Fiesta that can be purchased. You could be forgiven for thinking that a race between a bug and a Fiesta would be as interesting as comparing the relative viscosity of Greek vs. normal yogurt, but you would be wrong. These small chassis (yes, that's actually the plural of 'chassis') carry large horsepower and are consequently quite quick, albeit mostly in acceleration rather than top speed. Combine all of that horsepower with a rough dirt track and you've got yourself a real handful.
Tracks are also required. A few are provided as new versions of existing tracks, most notably the older (and lower cost) legacy tracks like Daytona and Phoenix.
It would be interesting to try it out and see how it compares to Project Car2 2 and DiRT Rally, both of which beat iRacing to the line with a Rallycross implementations. Both are quite fun - maybe I still don't really need iRacing.