The only thing that strikes me about all the "do what makes you happy as long as you can afford it, we only have one life etc." is that the individual 'you' can't afford it (apart from maybe the 0.01% with sufficient inheritance to do so). That's the whole reason people work, because an individual can't support themselves, let alone children as well, without money coming from somewhere (realistically someONE) else, whether thats a partner or the state.
So it's not about "you" singular being able to afford it but the "you" plural, usually your partner and nobody seems to be factoring in whether they would be happy working 40 plus years without a break to support the rest of the family.
Apart from the fact that in the majority of the country you'd need a wage significantly higher than average to do so (the days where a single "normal" wage could support 4/5 people are generally long gone) when does the partner get time to volunteer or do their hobbies or any of these fulfilling things people are suggesting OP could fill her time with if she never goes back to work? What if the partner turns around aged 50 and says "hang on I've supported this family the last 20 years by myself, I'm retiring, it's your turn to cover us all."
Obviously if the partner is happy to do so then that's great, go ahead. But there's a lot of stress involved in being solely responsible for several other people, particularly if having to do so you need a well paid (and therefore often intense and stressful)job. Not to mention what happens if that sole provider gets too ill to work, dies early, or decides to leave the family.
It's not as easy as saying do what makes YOU happy...it should be a family decision that everyone is happy with. Including what's best for the kids...yes there could be benefits to having a parent being around for them whenever they are needed, who can attend all school hours events, and mean they don't need to spend long days in childcare...but there can also be benefits in having additional money in the household (not talking about spoiling kids but significant differences like having their own bedroom, affording hobbies, being supported through university) and seeing behaviours modelled i.e. women's careers are as important as men's.