IMO its a combination of all the named factors. bj have to hit a nerve or to wait the music cycle in a way in order to have a hit like its my life. its a bit weird because even if they put out good songs thats still not good enough, they have to put sth timeless-refreshing etc etc...for many years i believed it was the poor single choises, and many times maybe they could/should have made better ones but now i dont really think thats the main reason...everyone has some favourite songs, that doesnt seem they d work as singles...having said all that i trully believe that because of jons choises-leadership and work eethic bj status improves and becomes more and more strong, they are classic not nostalgia, they avoided all the dramas(at leats most of them),no break ups,scandals,comebacks,remixes,farewell tour etc...and the public seems to aknowledge that.
every tour is bigger, their hunger for new music etc seems to be there so i honestly believe they are closer to become rock icons(if they arent already) than a nostalgia rock band.