"there is always an opportunity cost in terms of money not spent on loved ones" seems to me that by that logic you don't "love" yourself and you put very little value to yourself and that you only serve your loved ones. Everything that I purchase and that brings me happiness in term usually makes the people around me that love me also happy. Either by improving my mood and so improving my social interaction with them or simply because they care about me. And most of the things that I can and will buy for myself are transiently valuable to them as well. I buy an Omega watch -> someday I will leave that watch to my kid hopefully with a good story and a loving memory. I get a gaming PC/console -> I get to spend time with my kid playing a game. I build a utility room into my garage -> I get to teach my kid how to build/fix something. I buy a telescope -> I can spend time showing them the stars/galaxies etc. I do not buy something like that when there are more pressing matters at hand. However if we are meeting our common goals the money that we earned are for us to spend in whatever way we want, including giving presents for each other(even in the form of money). The freedom to care for ourselves improves our care for each other.

Where by large you mean 1000$? Why would you have to be a millionaire to be able to afford that? What exactly do you plan to buy for your kids?

Expensive holidays are not automatically better, by the way. You don't need a luxury hotel abroad, maybe kids would actually have more fun going camping.

Also everybody seems to be missing the point that those 1200$ from the article where a business expense, not a "selfish purchase" as such.