I think your mistake here is assuming the Speedtail won't
also be great to drive. Every current McLaren is, so I'm not sure why the Speedtail would be an exception.
And are a P1, LaFerrari or 918's capabilities really any more exploitable on the road than a Speedtail's? Might they be
less so, given the Speedtail has been deliberately designed as a grand tourer and has, in theory, the perfect driving position?
I think to look at the top speed alone also misses the point slightly. As with anything - a Land Rover's off-road capabilities, a 911 GT3 RS's track performance, an amphibious car's ability to traverse water - the appeal is in its potential as much as its outright ability. I drive cars almost every day whose limits are well beyond being safe to explore on the road, so why do they need limits that high?
The idea is that as the bar is raised, their capabilities are proportionally greater underneath those limits too:
Now the advert's obviously somewhat tongue-in-cheek. But a 2CV will indeed be quicker than a Ferrari if one's doing 70mph and the other is doing 65. The difference is that a Mondial will also do double that, so at 70mph it has much more ability in hand than the 2CV does.
Similarly I've taken an old 1984 Golf GTI to V-max on the autobahn - about 120mph. It felt pretty dramatic, but 120mph in the Bentley Mulsanne I took up to just shy of 180mph felt like barely breaking a sweat. The Bentley doesn't need to go anywhere near 180mph - the opportunities to explore that speed are slim, even in Germany - but it makes it a hell of a lot better car to drive at 120mph.
The Speedtail is no different, just with larger numbers. It's a GT; its USP is to do comfortably what other "normal" hypercars do giving everything they've got with noise and drama.
Worth noting that the F1's 243mph run was slightly cheaty - McLaren turned up the rev limiter to 8300rpm (
more than was safe for the engine, and more than Andy Wallace was willing to give another try after his run!) as at the original 7500rpm it stopped at 236mph. I don't think it really had any more to give...
As I wrote above, the ease at which the Speedtail does that speed is probably greater too - more stable, less on the limits of its capabilities (it'll get to 186mph
nine seconds ahead of an F1). I suspect 250mph is low-balling it slightly, but McLaren's problem will be where to test it. When I last spoke to them they had a few ideas in mind, but some of the obvious places are out - Nardo isn't suitable, and Ehra-Lessien is owned by the VW Group.