This is not true everywhere. Forward thinking dealerships recognize the truth of this article and have adjusted their revenue models accordingly.
As an example, I got to know the leadership at the DGDG dealer group in the Bay Area over the past couple of years, and they've fully embraced the notion that there's not much money to be made on the sale itself -- and the more you try to make, the more your customers dislike you.
Instead, they aim for the price you might be able to negotiate down to somewhere else, and focus on making it an extremely pleasant experience. The goal is for you to return for trade-ins, maintenance, and all other auto related transactions.