Much better to know that from the start than get surprised during interviews or after you start.
You've got people bringing home $150-350k/yr plus every imaginable perk fretting over the idea of putting in more than 40 hours a week. Even high-skilled high-pay workers (medicine, legal, and finance come to mind) put in lots of hours without whimpering about finding a balance, much less the vast percentage of the population who hold blue-collar jobs and clamor for overtime pay.
If someone doesn't feel they should work more than 40 hours, then by all means don't take that job, but please drop the damn sense of entitlement. This bubble will not last forever and one's ability to crank out an Uber-for-X clone in NodeJS won't always pay the bills.
It is possible to make a lot of money while working reasonable hours and solving problems that are a lot more interesting than "Uber for X" type shit. The fact that our industry values the latter while burning out inexperienced engineers who don't know better is definitely a problem though.
So now you've made this assumption.
I get what you're saying, but you also have to understand that there are people willing to give up salary for more free time, and these people are therefore allowed to ask for fewer hours. There's no entitlement here.
Developers overwhelmingly choose [2] "Vacation Time" and "Expected Work hours" as their primary attraction when choosing employers. HN users constantly [3] talk about achieving a "work/life balance" and sharply criticize any job which they requires work beyond ~40 hours/week.
So you have one of the most well-compensated career paths combined with the lowest barrier to entry and the primary things people are concerned with is minimizing their time spent working. You're damn right I'm going to call that entitled.
[1] https://docs.google.com/spreadsheets/d/1JR4KrVH1dygniLiLFAMT...
[2] https://insights.stackoverflow.com/survey/2017#work-what-dev...
[3] https://www.google.com/search?q=site%3Anews.ycombinator.com+...
If you think developers are overpaid, then just say that.