I don't think that all employers can offer 24/7 childcare, and I wouldn't necessarily want to see that happen, as it would put pressure onto parents, and more particularly mothers, to fit their family around work, rather than the other way round.
To me, there are two separate issues. The first is that everyone, whether or not they are parents, should be able, as far as possible, to plan their time and make arrangements knowing what their working hours are going to be. Clearly, this won't apply to everyone - police officers, and others who might be doing something unpredictable at the end of a shift won't be able to do that, but most people should. This would allow people to have childcare in place if they need it, and would also allow them to do things outside of work if they want to do that. Having everyone unable to make plans for anything (looking after parents, walking a dog, joining a choir, whatever) doesn't make for a cohesive society, and there is usually no need. On the odd occasion that someone needs to go into their workplace out of hours, I feel that their flexibility should be matched by flexibility from the employer.
The second, and more emotive issue is the one about SAH parents. I think that there should be choice in the matter, but I don't think that it's right to pretend that these choices are cost-neutral. Someone has to pay if capable members of the workforce are not contributing to the collective purse. People often say that they contribute in other ways, by keeping house and by volunteering, but working parents (and non-parents) also volunteer and also have family and housekeeping responsibilities - they are not peculiar to those who are at home during the day.
People who have stayed at home, not paying tax and having their NI contributions paid for them have been able to do so only because other people went to work and made those contributions whilst also paying for commuting and childcare out of their salaries. We don't have a system which asks the working parent to contribute on behalf of the SAH one, yet both parents have access to all the things paid for out of tax and NI, as do their children. I am not saying that this should not happen, but I find it astounding that those who have made the choice to stay at home can be so rude to the people who have worked to allow that choice to be made, and take the moral high ground by suggesting that working parents have let down their children - or worse, that there was 'no point' in having them if for part of the day they would be cared for by someone else.
As has been said, not all parents work because they want to. Some can't afford to stay at home, and it must be galling for them to see others doing so at their expense. Others could afford to stay at home but prefer to have financial independence, or may have other reasons for wanting to earn money or to go to work. Yet others are lucky enough to have a job that they enjoy, and feel that they, and therefore their children, will be happier if they are able to continue in their work - being brought up by a resentful parent is no picnic.
Similarly, there will be SAH parents who believe that they are the only people who should be around their children, others who didn't have a fulfilling career and prefer to be 'at home' (I realise that SAH parents are not tied to the house 
), and yet others who would earn very little after childcare, commuting, tax and NI have been paid, so don't see it as worth their while.
None of the above is 'wrong', IMO, but neither is any of the choices morally superior, or any of the effects on the children absolute. In my experience, most children love their parents (even the rubbish ones), and wouldn't hurt them by saying that they wish they had done things differently and worked or not worked - what happened for them was just the way it was.
