This goes back to my distinction between the icons an American native might pick and those a European might think of.

I had no idea who LeBron James was until I read this thread. Even famous American sports personalities aren't that universally known overseas. Babe Ruth and Meadowlark Lemon don't play soccer. If you want the best known American sportsman you'd have to field Mohammed Ali.

As for Walker, while those showed aired in thr UK and Europe they weren't particularly significant. If we're looking for TV series heroes to add to the list then the team has to include Captain Kirk, Kojak, and the Lone Ranger - and maybe KITT.