Garak, you're one of the few members that is intellectually smart and open-minded enough to at least understand the concept of operational viscosity, dispite your lingering thicker grade preference. But when you say a "thicker oil won't hurt, nor will running the specified grade" you're only partly right.
I'm biased about a lot of things. Thin oils, thick oils, monogrades, mixing, you name it.
As you're well aware, I do pay attention to HTHS, and just about anything on the market is "too thick" at ambient temperatures. I concern myself with HTHS, cold cranking/MRV numbers, and then VI, when it comes to viscosity stuff. When I say that thicker oil doesn't hurt, of course, you know those comments are qualified. It doesn't mean starting it unaided in -40 C and then hitting the highway with the pedal to the metal. It doesn't mean there isn't a fuel economy penalty, because there certainly is, albeit impossible for an ordinary person to measure. As for wear, with proper driving habits, it isn't much of a concern, as you note. We simply don't see a lot of worn out engines. We also have to be aware what is causing the wear, and it isn't just because the viscosity is out of whack at startup, which is technically the case with everything out there.
Basically, something can work, but not be "optimal," and our "best" choices always have to be qualified. There are many alternatives that will work in such a vehicle, all the way from Walmart Canada's Tune It 5w-30 to an expensive API/ILSAC synthetic to something in the way of boutiques. There's lots one can get away with, including a 0w-20 if it's driven a mile per day or a monograde 30 if the thing is never shut off. That doesn't mean either choice is advisable for the average driver.
As for the race, I wasn't completely disappointed. I wanted to see how the new cars and new drivers would fare, and I got to see some interesting things. Lotus and Manor had a terrible weekend, so we didn't learn a lot from that, other than the fact that Bernie and Romain and Pastor were mad.
martinq: That's where it does make sense to pay attention to temperatures. 15w-40 in -30 C is never a great idea (aside from oil pan heaters, I suppose). Certain vehicles will start when it's way too cold out for the oil in the sump, as anyone with a good battery and a vehicle with a carb will tell you in this province when it's -40 C outside, even with 10w-30. My Audi allowed for 15w-40 down to -20 C. It was out of the sump before it went even below freezing.
10w-30 is the usual call for North American diesels in that cold weather, yes, but as Overkill points out, caution is needed. My dad always ran 10w-30 in his diesels in winter, plugged in, but when it got that darned cold, he just used one of the gassers. If one is pushing the weather, one has to be prepared. To make matters worse, back in the day, synthetic HDEOs were a little uncommon. But, as I stated, one makes due with what one can, and compensates in other areas.
You don't need the best 0w-XX on the market to handle winter. There are ways around it. But, on the same token, running a 10w-XX, 15w-XX, or 20w-XX in our winters is done at one's own peril, and with some careful planning and preparations.