I think it'll be interesting to see what happens - they can't continue (well, maybe they can! Maybe they'll try!) just grifting and lying and suing anyone whose opinion they don't like. What are the options?
A) They realise they've played it very, very wrong for 6 years. They realise it's not working, based on opinion polls and advice from seasoned PR experts. They apologise publicly and privately to the RF and the British public. They admit they got it wrong. They live nice low key lives, only post themselves on social media (not their children) and they stay in Montecito, have a nice pint and wait for it all to blow over. Everyone lives happily ever after. Highly unlikely, based on their form.
B) They carry on doing what they're doing: faux royal tours, merching sick kids, speaking to tiny audiences on roundabouts, suing the British press and His Majesty's government, moaning and whining and complaining. They carry on being cold shouldered by anyone who's anyone: The Clooneys, the Obamas and most of Hollywood. They never realise it's not working and so we carry on these threads ad infinitum because there's still so much to discuss, because they are completely delulu, as the kids say.
C) Charles dies, William ascends the throne and either does nothing, carries on grey rocking and living his best life (most likely I think, it's worked well so far) or he goes nuclear, takes their titles, takes legal action to enforce the Sandringham agreement and sues them for defamation every time they lie about him or his family. He won't but I think we'd all buy popcorn and watch and enjoy!
I'm not sure what other options they have. I would have thought a return to the RF is highly unlikely - they've made themselves so unpopular with the British public, the press, the palace and their families that there would be a lot of resistance to this. We, the public, pay for the RF and I for one, don't want to give a penny to those two.
They should be ashamed of themselves but sadly, I don't think they are.