To answer the original question, SLF
are definitely getting worse.
As an engineer, I hold type ratings for most of the common types flying up and down the holiday routes. I don't know if this is a factor but I now find it almost unbearable, watching some of the behaviour I see around me when I travel.

Look, I don't give a toss if you hurt yourself by contravening the cabin crew instructions, in fact, I pray you do. It's just that by undoing your belt during the take-off roll, you stand a good chance of flattening the occupant in front of you if we have an RTO, you big fat slob, because the hinge pin will break and you must weigh about 260 + pounds (actual conversation!). Yep, nice one, really clever.