Terrible problem for tennis players, what with the toes banging into the front of the shoe constantly and those miserable foul socks! Courageous of Mac to do this! And he couldn't get the Lincoln gig after McConnaughey grabbed that.
It is sort of amazing that McEnroe is still famous enough to get any sort of TV ad.
I'd guess that in the US, McEnroe and Agassi are better known among the non-tennis playing public than Sampras or Lendl. Among the 'yutes' McEnroe is probably famous primarily for yelling "you can't be serious!" and appearing in Adam Sandler movies.