This is unrealistic. For computing devices it exposes too many security risks for example, if you say no to Windows feature updates, after a time, while the OS is supported, you won't get any updates at all) . For cameras, if you say no updates, you give up things like future lens compatibility.Just don't install it then.
Personally, I'm fine with canon's ultraconservative firmware updates. I treat my camera more like a tool or appliance, and in these cases, I want the devices to work on day 1 reliably, and stay working that way.