I agree that the intimacies of their marriage cannot be known and are, in any event, not really anybody's business but their own - though, in my view, how they are financed and what they spend is our business.
But the royal family actually welcomes this sort of coverage, designed to create a romantic (but perhaps sanitised) view of an ideal traditional marriage and to reinforce the notion that they "belong" to us rather than that we are their "subjects".
As for the comment to the effect that they have never, unlike Diana, courted publicity, that is absolutely incorrect. Some people may recall that in the 1960's the royal family was felt to be losing public support - particularly with the younger generation. In 1969 a full length documentary - perhaps the first example of "reality TV" - filmed the royal family over a period of time to show "the people" that they were really just like us.
It was viewed by over 30 million people and has been described as a "PR triumph". The previously worrying rumblings of public dissatisfaction ceased. How
sever, the queen ordered that the film - having achieved its aim - never be broadcast again.
They still welcome coverage of their comings and goings - but only when they have absolute control over what is filmed.