If your car never leaves your driveway, or the reach of your home wifi, sure! That's not the case for most people though.

Also, you can't do that if people don't cooperate, while it may be in your interest (ex: to track customers across the city)

As for the weather station, it involves you having a home internet - many people just have cellphones. A device that would ask for wifi passwords etc or require bluetooth pairing or worse would be complicated. Something that works worldwide with no setup would be a hit!

It's very easy to not perceive an opportunity which doesn't apply to you - in this case if you have say LTE in your car + on every device + at home.