You aren't accounting for purchasing power. In most countries, medicine costs half as much (or less), education is much cheaper, and the cost of food and housing is much lower.
Milanovic's figures do account for overall purchasing power. It would be pretty amateurish of an economist not to.
The distribution of the price level among verticals is a separate question though, and it's possible that it's suboptimally skewed in the US
Which is pretty easy to account for if one is being serious: https://en.wikipedia.org/wiki/Purchasing_power_parity