> Is it really a problem that some people work hard and take care of their kids?

Sort of. The article is about unhappiness in the society - including hard working child carers. It's not the reason for the problem, but it's a symptom.

> This seems disconnected from reality because I think one of the biggest job requirements these days is imagination and adaptability.

A person can be very imaginative at his or her work and took for granted some over-simplified models, like "unproven vaccines cause autism". Similarly, here imagination is needed to see the bigger picture.

It's a problem that they can buy their way into better opportunities at the cost of the rest of the population.

What’s the point of money if you can’t buy your way into a happier and more prosperous life with it, especially for your children?

At an individual level it makes sense, we would all do the same in that position. The problems are obvious when you step away from that and look at it from a societal perspective.