Not so long ago, things didn't look so great for the guitar, that global symbol of youthful freedom and rebellion for 70 years running.

With hip-hop and Beyoncé-style spectacle pop supposedly owning the hearts and wallets of Millennials and Generation Z – and so many 20th-century guitar deities either dead (Jimi Hendrix, Kurt Cobain) or soloing into their 70s (Eric Clapton, Jimmy Page) – electric guitar sales had skidded by about one-third in the decade since 2007, according to Music Trades, a research organisation that tracks industry data.