... yeah, apart from gyroscope, pressure, proximity, light, position, magnetic, accelerometer, g, fingerprint, blood oxygen, internal temp and IR sensors.

And some smart speakers are now loaded with thermometer and hygrometer.

All Home pod mini and the new big hompod has those

Because the demand hasn't been there. If more people learn the benefits of these sensors and decide they want more of them they'll pay more for models that include them and manufacturers will respond to demand. If people don't know about them, or don't perceive any particular benefit, those sensors will remain niche and expensive.

> decibel meter

You have the microphone in your smartphone.

Manufacturers believe consumer sentiment favors cramming more telephoto selfie cams and the like in to phones.

Unfortunately, word on the street agrees. I'd really love CO2, HRV and a physical keyboard, but it's just not gonna happen ever, because we'd end up with the Homermobile.

homemobile was ugly and expensive. if they could be slipped in easily and reasonably cheaply then it might fly.

Same reason I can't have a hardware keyboard on any modern, reasonably priced phone: lack of demand.

You can add these things via USB (not sure about iPhone). If enough people find it helpful, it'll become part of the package eventually.

There are a few lightning adaptors, I have an IR camera for example, however they are talking about the USB C port is going to be proprietary so it will only work for power unless you have Apple approved wiring and chips.

Probably because it would make it cost more than $1000 while not being useful to most people.

Because manufacturers invested a lot in advertising to create demand for extremely high resolution screen and cameras.

Even if air quality sensors would have saved lives (see covid and air pollution) that's not what companies optimize for.

iPhone has a decibel meter

Any phone has a decibel meter, it's the microphone.

However, I can imagine that with Android devices calibration is going to be an issue (with iPhones, you know which sensor is being used)