Flexible hours impose large costs in terms of increased difficulty of coordination and communication and if you’re really serious about them you need to completely upend the organizational structure, like changing an on premise company to a fully remote one. There’s also a hard upper limit on your career because managers are the bottleneck for communication so they almost have to be available when active else is. Arrangements to make flexibility economically profitable are also often denounced, see Uber.
> Even if you disagree that there’s a problem here (and I think you’re wrong) how would these changes cause harm? Wouldn’t it just be a better world if people were less stressed by these things?
It would be a better world but flexibility imposes large costs. Obscenely convenient childcare is also far from a panacea. Sweden has cheap to free childcare and it’s available 24/7 for those whose jobs demand it. But while Sweden’s employment rate is very high it’s among the most sex segregated in the world and fertility isn’t noticeably different from countries that aren’t so generous, suggesting the effects on family formation are minimal.