Net neutrality outlaws any conduct by the ISP to regulate or throttle off destinations by which site it is. Customers aren't doing it, the ISP is. Even Ajit Pai's proposal demands transparency so customers can make their own decisions, but net neutrality would indeed prohibit specific use Internet offerings.

Nobody could offer one because net neutrality would prohibit an ISP from intervening if you popped the SIM into another device to surf the web with it.

Google and Netflix are both against allowing such because streaming video, of which these companies own the largest providers of streaming video, would be the primary thing limited plans would all definitely restrict. Neither company wants ISPs selling Internet plans that can't use their video services.

Even if it'd be good for the customer.

> because streaming video, of which these companies own the largest providers of streaming video, would be the primary thing limited plans would all definitely restrict.

No, the primary thing limited plans would all definitely restrict would be the quantity of data transferred. That's what all the cellular providers already have the infrastructure to monitor and control. And once you've created an IoT-oriented tier of service that is limited to eg. 100MB/month, there's no reason to expend further effort trying to identify and block video streaming services.

I also don't see any reason why a provider couldn't offer a customer-controlled firewall option that disables access to everything but specific endpoints for IoT devices, especially if the "customer" is the IoT device service provider.