You can't add some random cars and 3 random tracks and violà we have "REAL LIFE SERIES". You just have a very little part of it. You perfectly know how bad they used SuperGT and other licences in A-spec, so what exactly make you think/hope/suggest "they could easily do another, Le Mans" ? Formula GT? An all seriousness that's a bit optimistic.
I think you're misreading what I'm saying.
I'm saying they currently DON'T have real life series in the game. They have the names, sure. But without the structure of the series at least moderately resembling something realistic, it's just not.
Which you seem to understand, and I'm not entirely sure why you think I'm saying anything different.
They HAVE at various points had the licenses, the cars and the race structures, but they have never put them all together. There's not really anything stopping them, as far as I can see. They just haven't done it.
Le Mans is pretty hard, as far as real life races go. But if you had a livery editor (not out of the question), a few different prototypes and a few GT class cars you could make a decent go at it. You're not going to get every team, but get a few and let the players sort the rest out. You're obviously not going to get 40+ cars on track at the same time, but no current console game is capable of that and you need a fairly good computer with PC sims to pull that off. 16 is a good start, and if they wanted to be clever there's trickery like FM4s passing challenges possible to make it look like there's more cars on track. GTA '10 showed that GT had at least been working on flag rules. I can think of no real reason why they couldn't do multiclass.
I don't see why it would be impossible to do in GT. I do see that they haven't really tried in the past, but I don't see that it's been a conscious decision on the part of the developers to say "we don't want to do real races".
You seem to think that GT will never do it and those of us that want it should bugger off to some other game. I still like GT (for all that I dislike GT5 specifically) and I want to see it incorporate new things like this so that it can grow as a game. If all GT7 has is the same Clubman Cup/Sunday Cup/etc rubbish, it's going to be on it's way to a slow death.