Start? Dianna and Fergie was full-on decline.
Charles has openly said the royals will be "slimmed down" when he takes over.
Dianna and Fergie were definitely part of the decline, but the queen was still there holding it all together. Once she is gone and the good will for her disappears it could really fall apart.
The amount of tolerance for dipshit Charles is going to be zip.
They'd be better off if William took over.