Plus, it's been shown that there's plenty of equally talented musicians as Bruce Springsteen. He just edged the others out by a process that we might as well call luck.
There is more to it than just hard work. There are a lot of people who would be able to put on a four hour show, but would people want to watch it? Four hour concerts are celebrated only if the entertainer can grip the audience for four hours.
His predilection for 4 hour long concerts was well known in the eighties.