Odds of Hanging On
As many people as there were competing for a slot on a team, that'’s the same number of people hoping to take your job from you if they can prove they're better. And the sport itself, if you haven't gotten this idea yet, is pretty rough. You'll take a beating playing hockey. Do that for a long time and it will take a toll.
The average NHL career lasts about 5.5 years. That means plenty of guys last much longer. Dave Andreychuk played for around 23 years and Chris Chelios lasted for 26. But those are the exceptions. Since 5.5 years is an average, that means plenty of guys don't even last that long.