I hate this attitude that there's something wrong with that. It's perfectly possible to be a good engineer doing only 40 hrs a week.
Frankly this whole attitude is a big part of why we have a diversity problem, because only a small minority (over represented here on HN) want to spend all their time building software and this attitude puts a lot of people who weren't teenage coding geeks off joining the industry. It's actively harming the industry and I wish it would go away. If you individually enjoy coding for fun above anything else by all means go for it and enjoy your life, but stop trying to force that on the rest of us. There's more to life that just building software!
That's great, someone is a better rounded individual. That's nice.
But if that well-rounded individual applies for a React position but has zero React experience, let alone any React project in their portfolio or CV, then that well rounded individual will be quickly brushed aside on the first round of the application process.
But at least he's well-rounded.
Just because some do doesn't mean most do, at least in any significant manner. Just because some don't doesn't mean that they are letting their life outside of work go idle. People are allowed to have other interests (e.g. hobbies) and other responsibilities (e.g family). That doesn't mean that they are suspect or not good. It may mean other things, like they are a better rounded individual.