Most people care about their personal well being and so the fact that so many ignore the current briefings tells us that they are not effective communication. Two of the main reasons, I suggest, are 1) that important information is bundled together with less important that is consequently boring with endless repetition and 2) there is no explanation of why the information is important.

As discussed above, important information obviously includes that which varies between aircraft, and that which can help people take rapid action. Unimportant information, I submit, includes telling people endlessly how to fasten a seatbelt, at least in the way that it's currently done. (The briefing can always say, if you don't know ask a flight attendant or fellow passenger. Also, there may be a case for asking people to practice quick release but that's another issue).

Information is only important if people believe it to be so. Hence, why not give more explanation. For example, note your nearest exit and count the rows because crawling along the floor may be the safest option because there may be smoke in the cabin. A more user friendly one page explanation in the seat back would also be helpful. It could mention past flights to show why safety procedures matter. Obviously, some will say such information would be too disturbing but the whole purpose of a safety briefing is to create safe practices and the current ones often fail because they engender a blase attitude amongst a large proportion of passengers. That endangers those of us who pay attention as well as those who don't.

I imagine that when the current mantra was devised many passengers would not have been used to wearing seat belts, and were more in awe of flying so that it was felt that they couldn't handle too much reality. It's time that safety briefings changed to reflect the current world.