It may come as a terrible realisation to those who still have a creative heart beating away inside them; others with less integrity, or a bigger hole in their pension fund may see it coming and decide to exploit it for all it's worth.
The sad fact is, the majority of bands which have been massively popular at some point in their career (typically towards the beginning) and have continued working together since will reach a stage where the public does not care about the new stuff.
They will pay good money to see you perform your old hits on stage, but your latest album will inspire nothing but indifference. By the time you are aware of being in this position, there's probably little you can do to change it.
It may not be obvious when the point of no return has been passed, and it won't be until several years of horribly lacklustre sales have elapsed that it can be pinpointed (in a similar manner to 'jumping the shark'). Only the most adept will spot it coming and make the correct move before it's too late (U2 did this twice; going from non-ironic rock band, to "ironic" 1990s multimedia experience; then becoming a serious rock band again. They are still selling boatloads of new material after almost 25 years in the business.)
If you decide to accept your fate and play the old stuff, this is what happens; You become a tribute band to your earlier selves. You sing the old songs to the people who grew up with your music 15 years earlier. You do not frighten the audience by playing new material that is radically different to the old stuff. In fact, it's probably best not to play anything new at all.
The financial rewards for following this route may be significant, but for all that, your opportunities to do anything genuinely new will be as nonexistent as those of Björn Again, The Bootleg Beatles or Led Zepagain1.
Bands arguably in this position include:-
- The Rolling Stones
- To be fair, the Stones still record albums of new material every few years. But let's be honest; when they go to see a Stones concert, what are most people wanting to see? The new stuff? Or (I Can't Get No) Satisfaction and Jumping Jack Flash? Exactly.2
- The Beach Boys
- The Beach Boys' career stalled as they became extremely unfashionable in the late-1960s. Although they continued to record new material of varying quality throughout the 1970s, they ultimately went down the nostalgia path. Carl Wilson's death in 1998 effectively heralded the end of The Beach Boys in anything but name. However, following a period of infighting between the remaining members, Mike Love became the sole licensee of the band's name for touring purposes, despite being the only original Beach Boy in that band3.
- Any band or singer on a "1980s nostalgia tour"
- Belinda Carlisle will sing 'Heaven is a place on Earth', Culture Club will sing 'Karma-fucking-Chameleon', and ABC will sing 'The Look of Love'. They sure as hell will not sing an obscure track from some "vastly underrated"4 (and commercial flop) album released in 1992.
I could go on, but you get the picture.
1The first is an ABBA tribute band; you can probably guess who the other two are meant to be.
2 In fact, it was a comment about The Rolling Stones becoming their own tribute band that inspired this writeup.
3Although longtime member Bruce Johnston has probably paid enough dues to be considered a 'legitimate' Beach Boy.
4Generic quote from the sole amazon.com review for any such album, which will also inevitably give it five stars, bitch about it not being a success and state that the music in question could show up the quality of the dross in the charts nowadays.