When Thin Red Line came out in 1998 he hadn't done a movie since 1978 (Days of Heaven) and yet he snagged all the famous actors to play in it: Sean Penn, Jim Caviezel (though he wasn't as famous then), George Clooney, Jared Leto, Nick Nolte, John Travolta and others. It's like they were tripping over themselves to be in his film.
But I can't fault the general public for not knowing him either. His movies are more "artsy" so he is like like an American version of Andrey Tarkovsky -- you have to really be in the mood for his movies, like watching Stalker or Mirror by Tarkovsky.