Some ensembles have no problems switching members out: Fleetwood Mac being the archetypal example, although that could just as easily be a trick of branding. Before settling on their “classic” line-up (currently absent Christine McVie, though there are rumours that she’s going to show on a couple of unspecified European dates), the only constants in the group were its eponymous rhythm section. What if they had been playing on other people’s albums? Is Bob Dylan’s Desire a Sly & Robbie record? I would use a more recent example, except that rhythm sections don’t exist anymore. A few years ago, Malcolm Gladwell was paid a considerable amount of money to give a lecture in which the decade between the Mac’s first recordings and their superstardom was evidence of his 10,000 hours to Tulsa theory, book and lifestyle tour. Which ignored the fact that the group was actually half-a-dozen acts over that time, and that they had the top five albums in the UK right out of the box.