I would say why not make the demo sample DLC cars/tracks, on rotation, so that those who wants to test them before buying could actually do that.
I tried the demo first, knowing I would buy it anyway just from all the good feedback I'd read. The demo was not very impressive if I'm honest. An update on Steam is badly needed here to lure more purchases and most of all enlarge the user base. This is such a fantastic sim, more people need to see and feel that with a demo that shows off rFactor2 full potential.