Attitudes have changed around KC3 and Camilla, especially post KC3's cancer. A lot of people are in the "it happened long ago, why rehash?" zone.
I just cannot see Diana gaining the level of sympathy she received back in the 90s before her own affairs were common knowledge. Any discussion of Diana will dredge up James Hewitt, Will Carling, Oliver Hoare and more, further sullying her reputation as Netflix, more than likely, will want as much controversy as possible, to drive viewership numbers.
Possibly more important to H, given the collapse of Netflix, there is the issue of inheritance. Irritate King pa too much then inheritance can go down to one pound...you can't challenge that in court! H's sainted mother, who he called an adulterer in court, has already provided an inheritance and even dining off her death would be less lucrative than having access to King Pa's private money