I think the GT academy idea kind of skews the point I wanted to make it the OP. Of course the initiative was an awesome one, and the quality it has produced over the years cannot be argued against, but with the way it's been set up and the coaching you get as a driver etc I feel the actual virtual skills you have don't really amount to anything. GT academy is basically 'race car driver idol' for sims, but rather than using the sim as your skill set its just picking someone up who wants to be a racing driver that also happens to have driven in a race game too. It's pretty much like getting a professional driver who's out of budget to go and drive Gran Turismo for a bit and get a place in the event..
For me
@Ghoults nails the point I'm trying to make in the OP to perfection.
Do I think a sim racer can go enter a top level race and be quick? No not at all.
Do I think a sim racer can go enter, say, the UK Ford Fiesta club racing scene and outperform Joe Bloggs who's doing his first event with no sim experience behind him and the same real world experience as his sim racing rival, yes, within reason.
The basics between sim and real life are the same. Inputs one the wheel, pedals, gears / picking out and perfecting racing lines / racecraft when in a position fight / multitasking fuel, tyres etc / consistency / "listening" to car feedback and transferring it to the road and all that stuff stay the same across both real and virtual.
Obviously the physical element of them both are wildly different and sims can never prepare you for that, but that isn't the point of the question. Everyone has to get accustomed to the physical aspects and the "fear". That doesn't matter if you have a sim background or not. Everyone driving out onto the track for the first time will have that, and the good ones will overcome that fear quickly.
What the question asks, and what I'm intrigued to know, is can 2 people, one with sim experience and both with the same real world experience and same mental disposition go into a race and who would be likely to come out on top. Would / could the transferrable skills of a sim racer be of use to someone in the real world.
As I said in the OP, yes I think sim experience would help.
Looking at myself, I know for sure that I am a better racing driver now because of sim experience than I was before when I used to race. I am certain that if I could race against my "pre sim" self I would, 99% of the time be able to outrace myself on the track.
Would I be faster over a single lap because of sims? Probably not to be honest. Would I be quicker sooner on a new track I've raced before on a sim, yes I think I would. Simply because I've had time to study it on a sim and trial and error different things. Think of Istanbul as an example, that little downhill chicane in sector one can be taken several different ways and requires quite a unique line and throttle application in order to take it quickly. In a sim that baffled me for a while, so I had the chance to work on it for several days, share experiences with other drivers and study data. The sheer amount of time I spent on getting it right is massively more than I would of had at a real event weekend. That alone would, in all probability, have bought me 2 tenths of a second immediately against the real world me if we raced together on the same track. Not saying in the practice sessions at the track the real world me wouldn't have worked it out eventually, but while he was doing that, I already had the answer and could focus on some other part of my programme.
So it's not a simple question, and it all depends which way we are looking at it. But I'm sure in my heart of hearts that in some situations, for some drivers, sim experience must be of a real world benefit.
Probably