said by Os:
The point is very simple. Verizon controls their network, and they can let whatever they want as a device to be accepted on it.
Charter can do the same. And Time Warner Cable has until recently, not allowed customer-owned modems in many regions.
With FIOS it's often a 2 device install, the ONT and the Router. You don't NEED the router as long as you're internet only and have cat5. You need the router for the TV if you've got the on-screen schedule guide.
There is no additional charge, beyond service, for the internet/phone equipment...
I don't think I'd have a problem with Comcast requiring me to use their equipment. Though I would have a problem if they told me my service would cost $50/mo and also I had to pay a required $7 equipment fee.
I think that's the problem. You can't run a restaurant where you sell a bowl of pasta for $10 and then charge $3 for a fork while not allowing customers to bring their own fork.