If I understand correctly, there is only minimal confidence on BITOG regarding the testing protocols set up by SAE/ILSAC, to achieve SP/GF6. WOW. Just WOW.
That's quite the leap, inferring that from acknowledging that the standards imposed on these ultra-thin oils are to ensure adequate performance under increased boundary and mixed regime conditions, that this somehow implies discounting the efficacy of those protocols setup by these agencies.
On the subject of very thin motor oils, the first area of concern has to be the bearings. Film strength and add packs must be able to compensate for lower viscosity. Toyota's answer is to make bearings out of polymers.
Honda's answer was to go with wider bearings, as I already noted. "film strength" gets tossed around a lot (look at the RAT testing) but the issue with bearings is lower MOFT offered by thinner lubricants (and lower HTHS) so the bearing configuration/design has to be altered to avoid hydrodynamic turning into mixed or boundary, which bearings aren't supposed to operate in. How that's achieved I'm sure includes a number of methods, but one of the easiest is as Honda has done, make the bearings wider.
After up top, the next focus must be at the rings. This is where it gets hot. The oil must run clean. Here Toyota uses DLC--Diamond Like Carbon, to mitigate coking.
This is compounded by the fact that ultra-light bases used in these oils are far more likely to flash-off (hence the increase in Noack and exception made to accommodate that) which would be the reason for mitigation mechanisms, like coatings, changes in ring pack design...etc to deal with this. Toyota of course really buggered this up at one point, as has GM (Saturn).
Engine temperatures are controlled by sophisticated ECU software, channels at the block for oil and coolant, and electronically controlled oil pumps, thermostats, etc.
And that's the case for any modern engine, whether it specs 0w-8 or 0w-40. BMW was doing this stuff when they were still spec'ing LL-01 with an HTHS >=3.5cP, same with Mercedes.
But you all already knows this.
Yes, so I'm not sure where the disconnect is here?
Working to mitigate the caveats inherent with ultra thin oils so that performance is acceptable does not translate into better protection, which was your claim. If the oil provided better protection, these mechanisms wouldn't be required.
It's about adequate performance while returning better fuel economy. Which translates to an acceptable engine lifespan where the wear profile has been validated, through extensive testing, to avoid things like obscene oil consumption and aligning with the projected useful life of the vehicle it is fitted to.