It depends on the job a bit - how easy it is to add in hours and what impact that has on other things. So if you wfh then doing a few more hours is probably no great shakes, but if you have to commute, pay for parking, work shifts etc then all extra time at work comes with cost and inconvenience attached too.
So much is reliant on having help or support available. When we lived v rurally I couldn't work outside of school hours as there was absolutely no one to do drop off or pick up. It's surely not that hard to realise many people have financial and logistical barriers to work?
Quite aside from all that, if I didn't have to I wouldn't. I like to see friends, give the dogs longer walks (coming into winter it's sad to think most walks will be in the dark as I'm at work when it's light), read, keep up with the news, cook properly from scratch and keep the house nice for the DC to come home to. All seems a bit beyond me when working ft. I'd like to be engaged with the DC schools and to attend events and performances whenever they're on. I'd like the DC to come home to someone and to be able to keep them home of they're poorly without feeling terrible about work.
There is so much life admin - vets, dentist, optician, GP, picking meds up from pharmacy - all easier and doable of you're not at work ft.
Things like sports clubs and brownies etc start at 4.30/5 and dc have to miss out if both parents are ft.
I can't believe you can't work this out tbh. Is your life experience that narrow?