I imagine it's because of the lure of pure-research and self-actualization and pursuing an area of study with almost no limitations. No idea if this is true or not, but this is how I idealize academia.
Opposed to "industry" -- where you're under constant pressure to figure out why some random docker container pull fails or mutating web hook won't let your pod be deleted. It's just not fun or meaningful. It's a slog and the needless complexity is doing nothing but increasing.
Yes, I think academics are susceptible to defining themselves by their work, truly being to devoted to their subject and it's open ended so you can spend as much time as you choose on it.
I think these things can all be true in industry though. I say this as an industry researcher myself that has struggled with work/life balance my whole career. In the more soul destroying industry jobs hopefully you can at least clock out at 5pm and pay attention to other interests, i.e. you don't have to care about work outside of work hours.
I actually think it's more to do with the person than the job though. It's about how much you value work/career achievements and recognition vs family vs hobbies. Caveat: some people genuinely have to work unreasonable amounts of hours to put food on the table for their family and that's unfortunate.
why? i dont follow. is academia so special there?