People don't listen to that preflight announcement stuff because they've heard it a hundred times before. People who've flown even a couple of times before don't need to listen. People who are on their first flight, where it's all new and exciting are paying attention.
So, no - I know how to wear a seatbelt and that my seat cushion can be used as a floatation device and to check where the nearest exit row is...yadda yadda yadda. I can stick my nose into my phone and I won't miss anything important.
What's needed is either to make those instructions INTERESTING (like the Southwest Airlines people often do) - or to only give the routine instructions to people who need it. That way, when something truly important comes up, people will pay attention.