What? I should not negotiate a better salary with a company on the belief that, in the long term, it will be better for… who? Overpay? How can I be overpaid if the company agrees to pay? Should I be more humble? Should I give up some part of my salary so the company can have more money in their budget? Which pie am I growing by not taking my part? Whose pie?
You should negotiate the best salary you can. What you shouldn't do is refuse to work for a company that's offering a better package than your current company out of some kind of principle because that company is also offering even better packages to employees somewhere else. Which is what you seemed to be advocating.
That’s just silly