I just think pop music is more of a young person's genre so 60 isn't really old but it kind of is for pop, in that it isn't what people are used to
The people who were at the forefront of the pop music "genre" (performers and fans) are now in their 60s and 70s. They still love music from past decades and some contemporary stuff. There isn't a use by date!
Stevie Nicks (born 1948) was at her peak when she joined Fleetwood Mac in 1975 aged 27 - her voice was exquisite. By the early 80s it had been ruined by drugs, smoking and alcohol. She sounded much worse than Madonna ever has! She got sober and worked with a voice coach so she made a comeback (of sorts) in the late 90s with a voice that was different but still good.
She's 71 now and sells out stadiums as a solo artist and with Fleetwood Mac. Whilst Madonna is ridiculed, Stevie Nicks is revered despite the (excellent) cosmetic surgery, waist length blonde hair and wearing witch-like costumes.
Give it another 10 years and maybe Madonna won't be the victim of misogynistic and ageist remarks.