I sympathise entirely - maybe the airlines should introduce a currency requirement. At check in you could state when you last had the brief and what amendment state the brief was at, and then be exempt from paying attention.
It could probably go hand in hand with a similar drive in the cockpit:-
Capt: "this will be a Grice 3 C departure..."
F/O: "Yawn...yeah yeah, I heard that one yesterday, and last week."
Capt: "ah, ok I'll not bother briefing the take off then."
I'm sure the pax would be delighted to hear that.....
There are also Memory Items ...
As SLF happened to me several time when alone on the business class that the cabin crew politely ask if I am aware of the safety briefing in order to skip it.
AN