Spinning Around was her Believe; a huge hit that revived a flagging career. She's not going to have another one. Age hasn't got much to do with it, Spinning Around did for Kylie what Believe did for Cher. See also J-Lo with On The Floor. Celine Dion with Loved Me Back To Life. Cher managed a cute little hit with I Hope You Find it similar to Kylie having a cute little hit with Dancing too. Cher being 50 and Kylie being in her early 30's is a moot point. They both smashed it when nobody expected it.
I’d actually argue that All the Lovers was her Believe moment. It may not have gone to #1, but I think most of the GP assume that it did, and it came at a moment where many assumed she was “over” because of her age (which is gross, but anyway).
When we say 'this was her Believe moment' not everything needs to be identical. It was her Believe in that she had a global smash late in the game, out of nowhere that re-started her career in all markets, made her tour the world, do all the big awards and have a multi-platinum album. That was a Believe.
Inflation has pretty much doubled from 1998 til now, so that would be around £8 and you can purchase a whole CD album for that in a supermarket now.
At 33 is late in game? It wasn't really out of nowhere, Light Years already paved the way for her 'imperial phase' which was Fever. The odds were not against her to succeed.
Well in comparison to the likes of Britney and Christina she was probably viewed by the industry as old. Remember Holly Valance making snide comments about not wanting to be singing pop songs in her early 30s or something to that effect?
Spinning Around and Head both came in her 3rd decade of being a pop star which IS late in the game, no matter if she was 33 or 53.
I remember so many ageist comments on Kylie in 2001/2002 - from the public, media and some celebrities. They were saying she is old, had a facelift etc. That was ridiculous.