There are two important aspects to this issue that are really separate:
First, love and relationships need to be worked on, and everyone must choose how to allocate their time according to their own goals. In other words, we each have to choose what to sacrifice for things we believe are more important in the long run.
Second, there are stages and times in our life where our decisions must be different than they would have been a decade ago, or would be a decade from now.
I can't really say that my relationship with my wife is more or less important than my relationship with my children, because there's no objective way to measure that, and it isn't a stark black and white choice. At this stage in my life I am spending more time with my children than with my wife. Similarly she is spending more time with them than with me. But we have 5 kids under 10 years old, and their needs far outstrip our needs - in other words we recognize that our whole family will benefit more if they have a good childhood and we have a good marriage, than if they have a mediocre childhood and we have a great marriage, or vice versa.
We are certainly putting aside other ambitions at the moment so that we can meet each others and our family's needs, because we recognize that in the long run we will value our family relationship more than we would value a stronger portfolio (career, financial, retirement, etc).
On the other hand that doesn't mean we're completely setting ourselves aside either - but we're allocating our time according to need, available resources, and our particular stage in life in order to meet our long term goals.
But the article is not saying we should put our children in daycare 24/7 - it's simply saying that a balance must be achieved, and many people have tipped too far towards the idea of "Great Childhood and Mediocre Marriage." It further points out that such families may believe they are providing a great childhood, but the reality is that the improper focus means that both relationships are suffering.