The Royal Family will end. Not yet obviously. But within the next generation.
People often assume institutions like this fall slowly and gradually. We see a bit of that already happening with the reduction in "working" Royals, far less favourable poll results than when Queen Elizabeth reigned, and the willingness of the media to be more critical of the Royal Family.
I have seen people commenting assuming this means the Royal family will end soon. I think they misunderstand what is happening.
But society is changing and the deference that Queen Elizabeth attracted can no longer be taken for granted. Colonies are no longer happy for the Royals to carry out cosplay colonial tours on their soil, and increasingly they will remove the King as their Head of State. But I think when the end comes it will be sudden and unexpected. Similar to the fall of the Soviet Union. A clear weakening of the institution, but then a sudden, and shocking fall.
The aftermath will be very messy though as the Royal family try and fight for as much of the states wealth as they can, using the courts if they need to.