Its a fallacy to call it a fallacy though. Sure, many forms of wealth is not zero sum, but some are. For example political influence correlate with wealth and is basically zero-sum. So larger economic inequality concentrate power among fewer people. This is pretty significant whether you consider it a good or a bad thing.
There's no doubt it's in our DNA. Forming groups with likeminded people is what kept our species alive for hundreds of thousands of years. And it's only been in the past ~150 years that we as a civilization have started to seriously care about the wellbeing of others unlike themselves. We've undoubtedly come a far way, but that's not to say we don't have much further to go. Fighting with our innate tribalistic tendencies is hard.
Why don't you give them a week off to have a trip around on their own with family (company paid with a certain budget) and share their pictures live to make a wall of family virtually on a landing page. Leaving comments would be beneficiary too
Thanks for sharing. Got almost the same experience in middle-east where a part of culture within SW engineers came to low quality of development and higher time spans. Though I guess the article wasn't consider the concept #TL;DR.