The McLaren takes this to an extreme, but this is not uncommon on cars in general. Even the oil needs to be changed if you haven't driven it. Tires rot just sitting there (think of tires as Li-Ion batteries; they rot whether you use them or not). Fuel lines get old and brittle whether fuel runs through them or not. Our VW van has the penalty of the thing burning to the ground if 45psi of fuel sprays on that hot exhaust, so I change them regularly whether they need it or not.
My wife's first motorcycle was something like ten or twelve years old. Only 4K miles! Which means it did a lot of sitting. Guess what I was doing the next winter? Replacing every seal and gasket while I had the engine on the kitchen table, because just sitting there the all rubber bits dried out and leaked like a sieve. It would have been better had the bike had closer to 20-30K miles on it, and it probably wouldn't have leaked (or at least not like a geyser).
Top it off with the fact that this car can go 231mph, and you want to make damned sure everything is up to snuff before you turn it loose. You want low-maintanence, turn-the-key-and-go, go buy a Toyota Camry. You want to go 231mph, even if you can afford the entry fee, know that annual dues are not cheap for that club.