And that is an issue, isn't it? It's different from making a hypercar - like the Aston Martin Valkyrie, say - which has all of the on-track performance of an F1 car. Sure, your buyers might not be able to extract the full potential from it, but that's only down to their talent. With the right training, or a 'hand' on board, somebody would be able to get the best from it.
But the upcoming BP23 three-seat hypercar will probably go to 250mph and, at the moment, McLaren hasn't figured out where it can demonstrate it.
Then there are the world's big high speed bowls like, say at Nardo - but given that knocked 10mph off of the F1's top speed in the 90s, you can see why the corner scrub of a constant radius bowl is too much for a modern hypercar to bear.
Which leaves a few options, but none are optimal. There are long runways - the kind of things the space shuttle was ready to use in an emergency. But the surface of these isn't always terrific. They're usually concrete and not always perfectly surfaced because a) the shuttle doesn't use them any more and b) military jets only use part of the strip. And besides, while they're long enough to get to a high speed, few, if any, are long enough to sit there for very long.
Then there are road events, or closed road sections, like Koenigsegg used last year. But you can close a road for as long as you like, it's still a public highway, whose surface, iffy run-off and wildlife you're still left at the mercy of. There are, obviously, companies that don't mind the increased risk of a nasty accident happening on a high-speed run, but I don't think McLaren is one of them.
Besides, proving your own top speed is one thing: after that, how do you let your owners do the same? There's the argument, which I totally buy, that it's fine if an owner doesn't use all of a car's performance, because they know it's technically possible to do so: one day they could drive a Land Rover over rock moguls, or lap a Caterham 620R as fast as a track will allow.
But how difficult does it have to be to access a car's limits, before they really do become pointless?