I am beginning to think that I needn't bother about the prestige books as there is almost no chance that anyone will ever actually use the stamps from one in real postage. Indeed, it must be even rarer a likelihood than the use of the labels - and I gave up on them for that reason.
It is, though, tough to stop collecting what looks like a normal Machin stamp! So I shall carry on. the books are attractive and sometimes quite interesting, if nothing else.
On the subject of the demise of Machins, I have written before about how the Philatelic Bulletin has been featuring fewer Machins in recent years but every issue has, I think, had one lurking somewhere in its nice-smelling pages.
Take a look at February 2019's issue. Apart from part of a 1p crimson appearing is a faded illustration of stamps generally in a graphic band on page 555, there is not one Machin in the whole edition!