Yes, everyone has their own combination of reasons to choose a specialty. More and more, people are making the "lifestyle" decision and choosing careers that will make their entire life happy, not just their work life. There are plenty of specialties out there for all of us, and if someone happens to love one that only demands 50 hours a week during residency I say lucky for them!
Y'all forgot one though: Emergency Medicine, while tough during some of the residency (you rotate through many other specialties, lots of ICU stuff), will allow you to work less than 40 hours a week when residency is done and still make nice money. You will be working nights and weekends, however, so you must be able to be okay with that. And the job is demanding, so I'd only recommend it for those who actually like the work, not just the hours.