Would a pressure reading TPMS system be offered by manufacturers if they already implemented the cheaper passive ABS based system?

As you said previously, TPMS gives a more verbose output than ABS based system. That's a pretty obvious selling point

Is it? My car doesn't offer it as an option, it only offers the ABS based system. Does any car offer the more granular TPMS system if they already offer the ABS based system to fulfill the legal requirement?

Would you be willing to share the make and model of your car?

2021 Honda Accord.

From the owner's manual:

Instead of directly measuring the pressure in each tire, the TPMS on this vehicle monitors and compares the rolling radius and rotational characteristics of each wheel and tire while you are driving to determine if one or more tires are significantly under-inflated.

There's no other TPMS option available for that generation (10th Generation) car at any trim level, not sure about the new 11th Gen coming out this year.

I was kinda in the wrong, that appears to be correct. Honda is advertising the ABS based system as TPMS and is not offering any "upgrades".

What does "ABS" stand for in this context?

It doesn't actually require the ABS (anti-lock braking system), but uses the ABS wheel speed sensors to count wheel rotations, so it's essentially a free way to add TPMS, no additional hardware required since ABS is already required, just need software to track wheel rotations.

https://en.wikipedia.org/wiki/Tire-pressure_monitoring_syste...

Anti-lock braking system

https://en.wikipedia.org/wiki/Anti-lock_braking_system