There are a lot of other options and hockey has gotten a lot more expensive (especially at the competitive level).
Pretty much all my close friends played hockey growing up (we still play beer league), but only a handful seem really keen on getting their kids into hockey. Among kids these days themselves, basketball, soccer, etc have grown in popularity, so there's less peer pressure to jump into hockey with everyone else (ie fewer kids are likely to ask their parents to put them into hockey, in addition to parents being pretty luke-warm about it themselves).
It's a really common topic of conversation - "are you going to put your kids into hockey", so it's definitely on people's minds, but like I said, it seems rare to run into keeners intent on really pushing their kids towards the sport.