The U.S. ratings show that she is not as beloved as some proclaim her to be.
You should never use the TV ratings as a measure of any player's popularity.
Nadal - Soderling got only 1.6
It does not mean Nadal is not popular in US.
And also the fact that Nadal - Djokovic got 2.4 does not mean Rafa and Novak are popular in US.
The TV ratings measure only the public interest to the specific telecasting event of a specific TV. In our case to the RG final as shown by NBC. It does not measure the popularity of the players.