I only listen to commercial radio in the car and coincidentally noticed today that jingles are back. I suppose successful adverts get copied.
You get fashions in TV too. I remember when almost all US TV (as shown in the UK) consisted of Westerns. Then cowboys were dumped in favour of lawyers who got pushed out by SciFi, detectives and then police procedurals. After that an outbreak of soaps involving the super-rich, hospital dramas, and then forensic crime. Not saying it's bad, many of the inspired shows are well made. Although the original CSI was first and best of the genre, I'm fond of NCIS and 'Bones' as well. I just wish programmes wouldn't travel in convoy, I like a bit of variety.
Less creditable are the floods of copycat antique, cookery, gardening, cleaning, reality, scripted reality, and house makeover programmes on British telly. Boring and repetitive. And while I'm in rant-mode, it's bleedin' obvious the main problem in Hell's Kitchen is that effing bloke who mismanages the enterprise, one G Ramsay…
What I want to see is on TV is a film crew turning up at a tidy persons home with an 'expert' who announces that tidiness is a mental illness, and a team who 'help' by filling the entire house with junk from a skip…

Dave