[_delirium]

Some operators do, mostly ISPs that lease routers to customers and retain a way to push firmware updates to them (for example, Comcast does this). But router manufacturers typically don't touch the device once it's out of their hands.

[jlgaddis]

Note that cable modems (all of them, not just from Comcast) download their configuration from the provider every time they boot up. Ironically (since it uses TFTP, for one), this is called "secure provisioning".

They might give you a web interface where you can configure certain settings (e.g. integrated Wi-Fi) but the ISP ultimately has at least some control over any cable modem connected to it.