The Eagles, in that line, are telling us that chasing after those highs and lows is never going to satisfy. Whatever that first rush was, a sudden rock stardom you could neither understand nor necessarily survive, the siren call of your first alcohol- and butyl nitrite-fueled binge on Bolivian Marching Powder, or whatever it is, you can't satiate an appetite like that. The're telling us you have to go much more basic than that. Love, maybe. A really good dinner with the people you enjoy, I'm thinking. An Eagles show that, yes, you may have to quit your job to go to. It's not a warning about life becoming progressively more dull as you get older. At all. If anything, they're telling us to break out of our mindless programming and to live more deeply, to go where we really will find those highs and lows, and yes, maybe to see more live shows.
Yes of course, it is after all a song written about a desperado!