Not sure what you mean by big deals, but your question seems sincere enough.
My answer is quite simply that the most cunning, devious and masterful of marketers - namely, Ferrari - has yet to play a hand in this game. They are seasoned veterans at these shenanigans and know that it matters less what you actually have done, rather more what you can persuade people that you have done (or are capable of doing). The Fiorano lap time, for example, is an uncontested benchmark that they serially use to market the prowess of each successive model. It's brilliant because it cannot be trivialized by any competitor - and their target customers predictably eat it up.
On the other hand, Porsche endured quite a lot of embarrassment whilst embroiled in their Ring debacle with Nissan. They spent a lot of money and effort effectively un-marketing themselves. They played right into Nissan's hand and ended up being compared ad nauseum to a car half the price.
It may be better for McLaren to be perceived as the fastest vs. posting a time - only to have Ferrari claim they are faster still. Witness the EVO article - if they can get words published to the effect that common opinion is that the P1 is fastest, why set themselves up to have that title stripped unceremoniously by Ferrari's marketing maestros? All the magazines and websites took the LaFerrari 0-186 MPH time of 15s as gospel before the monocoque even passed a single crash test. You see?
Further, McLaren currently enjoys, along with Ferrari, a public image of Forumula One pedigree and, in the F1, the one supercar of the past 20 years that is valued by the market above all others in the same timeframe. It really does not pay to be seen as scrapping downmarket (public perception, not necessarily mine) with Porsche, just as Porsche was with Nissan, when Ferrari can and probably will just happily position themselves as above it all.
All that said, my personal hope is that they do release a lap time and kick-ass video. I really want to see what the P1 can do. But, as I said, I think both options have strategic merit.
This is all nice (and you bring up some good points), except one problem: Buyers didn't care about GTR ring times, or the GTR altogether. That was actually a Nissan creation, media fascination.
Buyers (which many here are) didn't care. The sales numbers reflect that. Nissan barely sold 1000 GTR's in America last year. Other years, they sold under 900. Porsche may sell more GT3's alone than either number. The GTR is/was an absolute sales dud. Only the media and Carlos Ghosn shenanigans keep its viability alive. Internet fanboys currently keep it's name alive. On the contrary, buyers in this market don't care. Instead, they're buying 911's SL's, Ferrari's, Aston's, McLaren's, R8's, etc., not GTR's. The sales numbers (and their garages) demonstrate and reflect this. I will admit, Porsche took some abuse with the close Internet followers/fan boy types. But at the same time, the GTR could never test close to it's Ring times in independent hands anyway (your marketing discussion personified). Nissan certainly did a good job marketing their vehicle to the media/fan boys, agreed (though no one bought it anyway)! The GTR could be argued as a loss leader for Nissan (though I'm sure others will argue it helps their image in other ways, even if this is true).
And I don't think Porsche holds the RING as an absolute marketing tool the way some may feel. I think with them, it's important, yes (due to car set up, location, etc.). But it's also one part of a series of things they deem important (i.e., comfort, usability, reliability, endurance, etc.) once they decide to build a car. Remember, it was Nissan that made the 911 Turbo their original benchmark (as so many high performance/GT/Exotic manufacturer's make Porsche their benchmark); not Porsche. I think Porsche's a very (ahem) German, transparent company, who seemingly gets challenged with every new release and high performance car benchmark. It comes with the territory (and them being German) I guess?
Just look at how they've methodically and systematically upgraded the 918's specs and performance numbers the past two years, regardless of the initial or prolonged Internet speculation and perception during it's run up? Porsche's confident enough in their cars and buyers, to let them ultimately do the talking and marketing upon release. And Porsche's still improving the 918 right not as far as we know.
One thing we know for sure: Neither of these Hyper-Brids will be raced or experience prolonged track usage (unless the owners is willing to spend tons of money on upkeep). Therefore, any race track bonafides would be artificial, and a long use road/race track like the RING becomes more realistic to the real world, and actual owners/drivers.
I found your "down market" references laughable for many reasons ("down market" is in the eye of the beholder my friend, regardless of $$). But in order not to insult any manufacturer and risk possible banning (as I've seen it done here), I will leave that notion (and why) alone, altogether. But I will assure you (as many of you know), not all luxury, exotic or high performance manufacturer's have a quality image with actual buyers and drivers (or at least all of them), as opposed to compromised media, non enthusiast, investor types, or teary eyed dreamy fan boys perceptions. This could go for interiors, reliability, drive train origin, service, etc, by the way. But "exclusivity" doesn't always buy quality, or it's perception.
As a matter of fact: Many buyers of these Halo type cars will want exclusively/mostly the Porsche, The Ferrari and the McLaren for differing or even the same reasons, based upon the car makers various histories, past products, reputations, pedigrees, who they are (the car maker and buyer) and what they represent to them. So it's laughable indeed.
I do agree, McLaren's better off, winning the Internet war (having many of it's fans believe it posted a sub 7 or great time), especially if they didn't achieve one. Now of course, in some peoples eyes, this will be seen as a negative/blight on McLaren's part as well. But what are they do (pending "Tuesday" in the much awaited Bahrain of course).
Sports car/exotic/high performance, even McLaren and Porsche fans (like so many other things), just don't fit one stereotype, as you're making them out to be. Some will like what McLaren's doing, while others will hate it. Some will lose faith in Woking (especially those who bought into the initial hullabaloo, and claims in the first place).
On another note: I find it ironic, that many of the same fans, here and elsewhere), who were killing the 918 (before even really knowing anything about it); stating 'Who Wants An ECO Friendly Super Car? Give Me More Speed!!, etc."... Remember that/them?...These are now largely the same ones pontificating on safety and the benefits of being good public citizens. Gotta Luv It!
Wasn't it McLaren and Ron Dennis who brought this upon themselves with breaking records, 6:33/mood board times goals, all time down force, best track car ever, etc, Big Boi Talk, in the first place..??
Come on now. We all know if McLaren had posted a legitimate Ring time, many of these same fans (and McLaren for that matter) would be hailing it and the P1 as a landmark/benchmark achievement in motor cars and McLaren's history. But that's fine. And I understand why. And we wait for Tuesday......
I guess, I just consolidated various post into one.