Oh, they will be fine in the medium term as well. This is hot air that will blow over. It is a global phenomenon purely because of Kate's reach and profile. She is that presence in public life that people get used to and then are startled and disorientated when it is suddenly pulled without warning.
Very few public figures (royal or otherwise) have this global reach or can cause this kind of mass disorientation and lunacy because they stepped out of the public eye for two months. The overblown and hysterical nature of the photoshopping incident and the speculation on social media is largely due that absence. There is also the commercial aspect - her absence has cost royal photographers a chunk of their livelihoods, media, content; some small fashion houses of outfits or jewellery she would have worn on engagements, sales; fashion bloggers, content etc. It has also created a gap in social media activity for accounst that usually cover her. Her absence has created a tangible gap in people's lives and consciousness, for whatever reason.
She is as much of a global icon as her late mother-in-law, even though the two Princesses of Wales have very different approaches to dealing with the media, their profile and being global talking points. This will make her even more of one.
She needs absolutely nothing from photo agencies or the media but they need her for content as their audiences are fascinated with her. Once she's back out and about doing engagements, she will be covered. Photographers will rush to take her picture, her fashion will be covered, people will follow content about her, scrutinise her pictures and so on. We have a summer of royal engagements coming up - garden parties, Trooping, Wimbledon, Garter etc. She will be out and about with her family, happy and engaging. She will be fine. She can choose to only release family pictures on her social media pages and not distribute any pictures to the media even for birthdays, and still she will be fine. Her charities will all still work with her and she will remain the Princess of Wales and future Queen and she will remain popular.
She and William crave lower profiles so if any photo agency or media decides to cover them, fine, if they decide not to cover them, even better. As we saw with William on his engagement today, they are just carrying on and not acknowledging either the lunacy or the attempts to bait them into a response.
Social media and the chattering classes are a tiny and concentrated proportion of the public. Their manufactured noise is no indication of reality.