Some 60 year olds do wear diapers either for bed wetting or for urinary incontinence or bowel incontinence issues.
Although not all 60 year olds or older adults wear diapers but some do and it's perfectly normal and okay.
Some people live well into their 90s or beyond without needing adult diapers or having incontinence issues and others may have incontinence issues including urinary and bowel incontinence issues and need adult diapers.
Some older adults or adults in general including 60 year olds may only wear incontinence pads or pull up style diapers and may only have slight wetting issues.
And then there's also some 60 year olds and other adults and even kids and teens that love to wear diapers.
I'm an adult myself and love to wear diapers and wear them 24 hours a day and would rather wear diapers instead of using the toilet.
I'm more happy in diapers as well.