If not, then how does the ISP get the Internet and provide it to clients like me and you, thereby charging us for it?
No. Only houses that 'burn' something to provide heat gas, propane, wood, etc. Our house has an electric heater no need for the detector. Also, (you did say EVERY house) some homes in very temperate climates do not even have heaters, so no need for the detectors there, either.
In any house with fuel-burning appliances, fireplaces stoves, heaters, boilers or water heaters, including but not necessarily limited to oil, kerosene, natural gas, propane, wood, pellet, peat or coal - yes. Otherwise, no.
An all-electric house, without a fireplace, pellet stove, or anything similar, doesn't really need a CO detector.
I own many houses and they all have gas heat and a lot have gas appliances. I installed carbon monoxide detectors in all of them.
