Cover bands get no respect. They get paid, generally a lot more than the average local band playing original music, but no one remembers them the next morning. No one buys their records, if they even bother to make one, or wears their T-shirts. A cover band is basically a living, breathing jukebox.
It's a tough gig. Playing covers requires massive instrumental chops—if you're going to play "Sweet Child O' Mine," you'd better be able to hit those high notes or play a reasonable facsimile of a guitar solo that's encoded in most of the audiences' DNA. It demands a Zen-like suppression of ego—people can tell when you're going through the motions for a paycheck. You have to hit just the right mix of the familiar and the unexpected—"Stairway to Heaven" and "Achilles' Last Stand" are equally likely to clear the dance floor, the first because everybody's heard it too many times, the second because nobody knows it. (It's the 10-minute track that leads off Led Zeppelin's Presence.) Aside from studio session work, playing covers for a living is about as close to punching the clock as a professional musician's life gets.
But it's not always about the money. Or maybe it is always about the money, it's just not always only about the money.
Most musicians learn to play by playing other peoples' songs. Millions of Americans between 30 and 50 who can't otherwise play a lick can probably run through the main riff of Deep Purple's "Smoke on the Water" on guitar and feel some slight satisfaction from it. The act of playing, and performance, is every bit as much art as songwriting. Is "Suspicious Minds" a great song because it's just a great song, or because of Elvis' performance? (It's the performance.) Does anybody really think Frank Sinatra or Ella Fitzgerald are lesser artists because they were interpreters of material other people wrote? (If they do, they shouldn't.) Are you more likely to dance while listening to your stereo or attending a concert?
Being a musician and being a songwriter isn't the same thing; being good at one doesn't mean you're good at the other, though they sometimes go together. It's only been in the last 45 years, since Bob Dylan and Sgt. Pepper's Lonely Hearts Club Band, that pop music has had auteurs. Before that, singers were singers—and singers were stars—while songwriters were mostly anonymous schlubs in New York office buildings. Now songwriting is a matter of credibility—one of the few concessions many mainstream critics make to Taylor Swift is that at least she writes her own songs.
Mostly we underestimate the power of familiar songs played well in the right setting (i.e., in a bar after a couple of drinks). We call them "guilty pleasures," but we don't really feel any guilt at all, and we shouldn't. "More Than a Feeling" is a great song, period. There's no need to justify it. "Billie Jean," "Psycho Killer," "Smells Like Teen Spirit," "House of the Rising Sun," "Satisfaction"—all great songs, and all likely to be played by the bands featured here. They each have different styles, different motivations, and different specialties. They all like what they do and recognize its limits. And they all want you to have a good time.