Many products have multiple stakeholders. I can't think of a single product that exists "to render dispassionate information" and nothing else.
AQI is unique in this case, in that it is a color-coded interpretation of combining multiple underlying objective values (PM2.5, etc.). And different governments have chosen different official national schemes for this, according to what they want the population to consider "normal"/green.
Which means that air-polluting industry in one country might lobby for a wider "green" band. Nothing like that is happening around temperature or humidity as far as I'm aware on iOS.
(Though I do believe Beijing had a history of under-reporting official maximum daytime summer temperatures, since people couldn't work outdoors above a certain threshold.)
Like producing food? A wider green band than what, the Netherlands map?
I think it's nice to be able to aspire to live in a green area. That one leaves little options, and paints a bleak picture.
And as long as ice continues to freeze at 32°F and water continues to boil at 212°F, I don't think anybody will be questioning the accuracy of the thermometers they buy.
Factors like building shade, vehicle density, wind cover, terrain, cloud coverage, and variations in humidity, mean that thermometers placed at different points in any selected area will report massive variations in temperature, and the naive (and impossible) approach of even distributions of identical sensors taking measurements at the same clock times placed across some given weather area will yield numbers that are not helpful for most people.
For example, about 1/3 of the area of Burbank, CA is recreation and park spaces that are in the verdugo mountains, at their highest point within Burbank limits 1800 ft. above sea level, and with almost zero residents. The other 2/3 of Burbank are about 600 ft. above sea level. How would you offer a number that summarized the weather in Burbank?
Imagine factoring time into this. There is no temperature of the hour, there are individual measurements taken at specific moments in time in specific places, using differing methodologies, different equipment, variations in MoE, and at varying frequencies. Put all this together, and the work of the observational meteorologist to produce daily or hourly temperature averages becomes extremely complicated, and the first question they would ask is, "What will the averages be used for?"
Here are some examples from the large literature on these problems:
https://www.tandfonline.com/doi/full/10.1080/07055900.2015.1...
https://www.sciencedirect.com/science/article/abs/pii/S00221...
https://link.springer.com/chapter/10.1007/978-1-935704-35-5_...
But nevertheless, a correct, objective, dispassionate temperature reading for that coordinate does exist in reality. And the phone's weather service is trying to approximate that as closely as possible. And you can objectively measure the error to improve future models.
My point is still that this is qualitatively different from composite air quality indexes, which are politically designed, and therefore designed differently for different countries.
You sound like someone who has never lived anywhere that people bitch and moan about the temperature on the weather reports being wrong because people think it's warmer than weather stations report, and get into arguments that the weather stations aren't placed correctly.