Like anything if you go above and beyond your wages worth in value companies take interest in you. Every job can can be looked at as human capital, and what you offer dictates where you go. To answer your question, I have seen mechanics get into management related positions due to there knowledge on practical applications and theory.
To get a unionized job as an elevator mechanic is extremely hard to get into. People with military backgrounds can get in through programs such as helmets to hardhats if there is an intake. My union values people who serve and it tends to be a meal ticket for most. Other then that, its unlikely that people will get in unless they have prior experience or know somebody in the industry during an intake
There are around 5000 union mechanics in canada
A lot of options. I work with mechanics who are on call along with there 40 hour work weeks, which gives them a guaranteed 2 hours extra a day even if they dont get the actual call. Not exactly my cup of tea, but these guys are pulling in lots of money working the extended hours. Considering all OT is double time.
Mechanical related trades are a good investment if want to go the trades route.