People buy all kinds of stuff online, why not this device? Unless the game uses HDCP the hdmi rip is not possible to detect. And the usb controller could even forward the properties of the connected device. These devices exist as we speak
I think just purely off of the additional effort—a cheat that requires a second PC and specialized hardware is simply going to have fewer users than something you can download and run. Some portion of people won't care enough or will have some sort of other issue with the hardware setup. I think generally these things aren't about making it impossible so much as reducing the frequency.
