At the risk of being pedantic, you keep saying the car's "computer" knows the individual tyre pressures but don't provide any "proof" that this is true.
TPMS works by placing a sensor in each tire, which transmits the pressure within that tire to the vehicle. And if the computer is alerting to low pressures, it would have to know the pressures. The only system I am aware of that does not actually know pressures is the indirect TPMS system, which uses the number of times a tire rotates as a proxy for (relative) pressure, and operates through the ABS. But the Outlander has a direct TPMS system, which I proved when I pumped up the tire and the low tire pressure light disappeared immediately.
As I pointed out, TPMS was NOT implemented in the launch PHEV, so has been added in later. If you are right, then there would have been no reason not to include it initially, but if it is a separate "add-on" system, then you might be wrong.
You're now suggesting that they strapped an "add-on" system that does the receiving, AND has its own CPU to do the processing, and then simply sends an alert to the main computer if one of the pressures gets too low? I suppose it's possible, but that would be even more expensive. Plus, they actually implemented an "A"/"B" tire set function through the user interface, where you can tell the system that you want to change the set of tires you have on the vehicle (I'm guessing this is for winter tires).
I am aware that the US market expects to have individual tyre pressures and location displayed but I don't know how long it has been a common feature there - perhaps you could enlighten us? However, AFAIK it is a novel concept in Europe (and possibly Japan) - again perhaps other readers can confirm this, as I had the same Toyota for 16 years before the PHEV so may have missed its general introduction prior to 2014?
TPMS was required in the US starting in 2014. My old car was a 2000 model and had no TPMS. Up until I purchased the PHEV, I thought that all TPMS systems displayed individual pressures, but apparently some cars do and some cars don't. On Toyota, I believe the Camry XLE submodel displays individual pressures, while the LE does not. Nissan seems to display individual pressures in at least some of their models, regardless of trim (i.e. the Rogue) and Porsche also displays individual pressures in their Cayenne (so no, I don't think it's a European thing to not do this).