Yes, companies sometimes push employees too hard. Lately in engineering though, you can punch the CEO in the face and he/she'll say "Sorry, please don't quit", with the current market. Obviously not true of all IT positions, but in engineering, it almost is.
So there's really no reason to screw over your work life balance, aside for maybe a pager rotation for emergencies (but the company should have a level 2 or 3 support to handle he common cases...I guess those guys work/life balance is fucked. Sorry)
Engineers however, are arrogant as fuck, and want to be at the top of the food chain, so a couple of them will willingly fuck over their work life balance. Then they'll get promoted for it (which is a problem with the company...but its hard to say no to someone who delivered twice as much for the same pay, even if he/she screwed over their life over it).
Then, people will feel they have to do this to compete. And thus, the New York Times Pseudo-Amazon is born.
Employers should not reward those people, and other engineers should NOT worship them. You don't need a union to make things reasonable, but please for god's sake, don't encourage your peers who do that shit.