Safety briefs are like checklists - the more often you do them/listen to them the more familiar they become, right up the point where you know them, off by heart.
I know my kids names off by heart, but whenever I get annoyed with them ( and placed under stress) it is amazing how many times I will use the wrong name. The refresher immediately prior to the (potential) event, places the routine/mundane/previously learned, information back in the forefront of the short term memory. This is important as the fight or flight response during a sudden high stress event, seems to rely on this information and that which is instinctive.
I too am a professional pilot - 25 years in my case. I don't need to listen to the safety brief.
Same here 25 years + but for the reasons I have given above I
do need to listen to the safety brief, and in view of my profession I also may need to assist. Just as when I listen to the flight deck briefings, I am making a mental model of what might happen and what my role might be (even if it is only to get out as quickly as possible). Situational awareness doesn't stop because you have placed your flight bag in a hat bin.
Pilots will be especially aware and are sometimes guilty of complacency, but we should guard against it. It is not infrequent flyers that are likely to be the problem, but rather (as shown here) those that feel a short term emergency refresher should be ignored in order to rely on that they learned some time ago be it last year, last month or even yesterday.