Secret communications with Comcast X1 TV Setvice

I recently discovered with a confirmation by Comcast tech support that when a customer subscribes to the X1 service on top of the regular TV service, the set top box, commonly known as the cable box or the descrambler box, communicates with the Comcast-issued Internet modem via a secret and invisible wireless signal so that the content of the X1 service can be displayed on the TV. This means if you move or turn off the power to the Internet modem, this X1 service will not work. The regular TV channels should still be there but the interactive guide about the shows will no longer be there.

I don't understand why can't the set top box do the X1 service natively on its own. It gets the TV feed on the same wire that has the Internet signal so why can't it use this same wire for the X1 services? If it can communicate with the Internet modem via this secret wireless signal, it can surely communicate with the X1 server directly. Why bother to hop to the Internet modem to relay the X1 information? When the handheld remote control navigates the X1 menus, does it communicate with the set top box or the Internet modem?

Just because the Comcast tech support person said so, I still think she was mistaken about the necessity of the set top box communicating with the Internet modem via a secret hidden wireless signal. This makes no sense from an engineering perspective. Comcast is not a small company. It surely get this done.