Out of curiousity, how old are you? Those were probably the biggest names in basketball in the 80s. It's also possible that they are known in Europe due to being co-captains of the first US Olypmic basketball team to allow professional players (Though they were past their prime at that point, and the remaining players were near the top of their NBA careers).
Sure, now that you mention him. And I'm sure I'd recognize some other old names upon hearing/googling, too. Just not in my active memory as basketball is a bit fringe sport around here.
Well, I know who he is, but from a sample of not-very-many in the UK, my wife had no idea and my colleague sat next to me (male, early 30s, loves cricket) also had no idea.