Denmark McDonald's prices are among the highest in the world.
https://www.numbeo.com/cost-of-living/city_price_rankings?it...
https://www.numbeo.com/cost-of-living/city_price_rankings?it...
Even if you blindly assume that revenue is tied to salaries, are salaries in the US only 20% apart?
Your citation also points out that a McMeal in Spain is cheaper, and I'm sure that quality of life + benefits in the US is even in the same division, specially give that Spain has free healthcare for all.
The truth of the matter is that workers in the US are massively exploited and abused, and that as a deep impact on everyone's quality of life, even the privileged.
$10 is a little misleading, as that's the very topend places in USA. Check out El Paso, it's closer to $6.