I remember Jimmy Saville saying (and this was approx. 30 years ago) that he had no idea how much he was worth and that if he wanted to find out it would cost him approx. 30,000GBP in accountants fees. (That figure alone is worth approx. 250,000 - 300,000GBP at todays rates).
If someone doesn't know how much they are worth how the heck does some hack know how much someone else grossed from a single album/tour.
And of course the royalties didn't just stop after the year of release and I am sure MK is still receiving them to this day.