Maybe this won't go well here but I can sympathise with passengers who do not pay attention to safety briefings.
I try and look like I am paying attention out of politeness but after hearing the same briefings over and over again, it is hard to switch on.
It is a question of how we work around human behaviour. Telling people they must pay attention really doesn't work as much as we would like it to.
Many travelers have been on consecutive flights over several days and had the same briefing telling them how to fasten their seat belt and where the life vests are and that the emergency exits are where the crew are pointing (and the crew then wave their hands forwards and backwards which doesn't actually tell you where *your* nearest exit is) and after say 4 or 5 times hearing that same script and demonstration in the last 24 hours, any wonder people turn off?
What can be done? What is the needed information passengers must be familiar with?
For a first time flier, maybe how to fasten a seat belt but for most people, hearing that part of the briefing is the signal to switch off - the majority of travelers have been able to fasten their belts for years and being told and shown how it is done wears thin.
I do not have many answers to how this can be resolved but some of the videos that employ some measure of humour and novelty at least grab people's attention (like funny adverts - however even then seeing the same video time and time again gets tired). Maybe multiple videos not the same one every time so you get to see some novelty?
Really important things that make a difference in an emergency could be reinforced in other ways, not just the briefing.
Where is your *actual* nearest exit? (and the next nearest in the other direction) - perhaps each seat back should have a label indicating that for that seat?
Do not retrieve baggage from lockers in an evacuation. Perhaps labeling that on the lockers and on boarding passes?
The brace position - illustrated on the back of the seat?
Oxygen mask deployment and use? I don't know - but being told it in the middle of a script after people have switched off perhaps isn't working that well.
Much effort and money goes into analysing human behaviour, working out how humans' attention and interest can be grabbed by people selling things in the in-flight magazines. Perhaps some of that effort and ingenuity could be used in working out how to inform people of essential things they need to know when travelling in an aircraft?