Let's use simple logic here. Parallels are being thrown around from sleighing through sailing to equestrian sports that use some sort of tool (or animal) to compete. At the end of the day it always comes down to the difference between the sports(wo)men, and their ability to be superior over their opponents, which includes the sense for choosing the right tool to be successful. Of course, the "right tool" is not necessarily the "better tool", but more like the "suitable one" (let's suppose everyone uses pro-tools, not going against sticks broken off a hedge). Thus one kind of bow for example is not better over another one, it may just be more suitable for the person using it. On the other hand, there are more complicated tools, such as a bobsleigh or a sailing boat, which could easily make much difference, thus the IOC took a simple move: standardize them. No unfair advantage over other competitors.
In the same way, there should be standard, equal motor vehicles used at an Olympic challenge if considered, which makes the debate on the ratio between man and machine irrelevant due to everyone sharing the same percentage, thus making the competition mano a mano.
Now this all seems fine, but I can already hear you complaining that motor vehicles are WAY too complicated "tools", so a failure of one component could be the judge between winning or losing. Quite right, I shall add, but what about horses? When an equestrian hits the field in the pentathlon for example, there is an unpredictable percentage of performance credited to the horse. For one reason, there are no two identical horses (until they decide to clone them) and for another one, a horse can have a bad day too, so to speak. So if a horse does not feel like hurdling in the finals and stops in front of the first gate, that is indeed a problem cannot be solved. In the same way, a failure of a component in a motor vehicle is one of those unpredictable factors cannot be foreseen, making the horsepowers no less eligible at the Olympics than horses.
By following simple logic there seems to be no way why motorsports could not qualify as Olympic sports, the problem is rather different.
The real question is, what sort of motorsport should head to the Olympics? Because the world of motorsports is about as varied as the universe of sports in general, motor-powered competitions could in fact have their own Olympics (and they actually have). But let's stick to the topic and suppose one could delegate one motorsport to the Olympics, what would it be.
Many would instantly say "Well, of course F1 should be the part of the Olympics, because it's the king of motorsports, blah-blah-blah...". It would almost seem reasonable, but there are multiple problems here: 1. "King of motorsports" is decided upon personal preference, it does not have anything to do with the amount of money involved or viewers' figures; 2. See problem above on equal cars, but an A1GP-sort of event would still seem reasonable; 3. Why open-wheel single seaters? 4. Why circuit racing, why not (insert any sort of motoring competition here)?; but most importantly 5. Why four wheels, why not two (three, etc.)?
Let's start with one of the most obvious problems: the sort of racing. Keeping in mind that the vehicle is just a tool, the competition could be bent and likened to any other Olympic sports. Cutting to the chase, I believe a time trial would be most appropriate over head-to-head racing, because it is the purest form of competition: who is fastest? The question is whether you look at motor racing as the 100-meter sprint or wrestling. As a matter of fact, head-to-head racing cannot be looked at as pure wrestling, because all the wrestling would happen during running. Yes, it includes a more complex driving technique but if someone is put into a gravel trap by someone else, there is no repeat, no second try, that position is lost forever - due to the fault of someone else. A time trial on the other hand eliminates all these problems and concentrates on pure speed. While wrestling cannot be conducted by any other means, motorsports can be. Whether it is conducted on a circuit or a point-to-point stage, it is almost irrelevant, but a circuit in a stadium is of course more comfortable for attendance and a lot more easier to broadcast.
The vehicles. Heavy compromise. Universally motorcycle and car racing are the two most popular and most practiced motorsports, at least at the beginning these two could be delegated. The vehicles themselves could be easily picked, just take a look at the "Race of Champions" - which is by the way a de facto Olympics of car competition. 3-4 types of vehicles used through the whole event, so drivers from different backgrounds ave a mixed experience, somewhat equalizing the chances. There is only one problem with this one, and the whole issue in general: Environment. The spirit of the Olympics (uniting people, peace, unity over differences, etc.) includes protecting our environment, thus rubber- and petrol-burning cars going sideways are definitely not the right message the IOC would want to get through. It should showcase new technology, sending the right message, so what else than some electric cars and motorcycles? Moreover, something designed specifically for the Olympics, not based on any other existing models, further emphasizing the challenge between drivers.
It all seems reasonable in my mind: a RoC-type of event where drivers are representing nations, with vehicles sending out the desired message correlating the spirit of challenge and the future.
If this is too much at once, the idea could be scaled down a lot: because if equestrian challenge is part of pentathlon, sure, driving could be part of it, too (which would make it... *gulp* sexathlon?). A short circuit/special stage/hill climb as part of this already complicated challenge could be a starting point for sure.
But this is all just speculation and playing mind-games. Why not just go for the obvious? How about an Athens to Other City Hosting The Olympics endurance rally? Like the legendary Peking to Paris, London to Mexico, London to Sydney, Liége-Sofia-Liége, Paris-Dakar rallies. Virtually following the route of the Olympic flame, instead of a sprint session, it would be the marathon for cars, trucks and motorcycles. A road rally with special stages here and there. A rally where all sorts of drivers from all sorts of backgrounds could jump in and be competitive immediately.
Can you imagine that? Athens to London? Athens to Rio de Janeiro? Winning an Olympic gold medal at the end? I think everyone can...