No, it’s actually way cleverer than that. @devoursjohnlock touched on “John erasure” over a year ago in this meta (x), but basically, in the Case-Book era of stories, or rather, everything written from The Valley of Fear and after, Watson starts to downplay his own role in the cases:
Now for a moment I will ask leave to remove my own insignificant
personality and to describe events which occurred before we arrived
upon the scene by the light of knowledge which came to us afterwards.
– The Valley of Fear (1914)
There remain a considerable residue of cases… […] In some I was myself concerned and can speak as an
eye-witness, while in others I was either not present or played so small
a part that they could only be told as by a third person.
– The Problem of Thor Bridge (1922)
His Last Bow (1917) is written in third person. The Adventure of the Mazarin Stone (1921) is written in third person. Holmes narrates two – The Adventure of the Blanched Soldier (1926) and The Adventure of the Lion’s Mane (1926) – and Watson isn’t even in them. People are really indignant about John’s diminished role in S4 but the fact is, it fits with canon perfectly.
But when you look at the other Case-book stories, you realize that while Watson leaves himself out of the surface narrative, he’s actually using the cases to vague about his own life’s drama in far more graphic detail than would ever be otherwise appropriate. He’s using his personal turmoil as inspiration; he’s using characters as mirrors to blab about his own private affairs. And then, in case you couldn’t figure out that was what Watson was doing, Watson writes up a case where a guy literally does this:
Could I have believed that a gentleman would do such an act? He wrote a
book in which he described his own story. I, of course, was the wolf, he
was the lamb. It was all there, under different names, of course, but
who in all London would have failed to recognize it?
– The Adventure of the Three Gables (1926)
So while in some ways John is erasing himself from the narrative, in other ways the narrative is more about John than ever. Just like S4.
Apart from these unfathomed cases, there are some which involve the
secrets of private families to an extent which would mean consternation
in many exalted quarters if it were thought possible that they might
find their way into print. I need not say that such a breach of
confidence is unthinkable, and that these records will be separated and
destroyed now that my friend has time to turn his energies to the
matter. There remain a considerable residue of cases of greater or less interest
which I might have edited before had I not feared to give the public a
surfeit which might react upon the reputation of the man whom above all
others I revere.
In some I was myself concerned and can speak as an eye-witness, while in
others I was either not present or played so small a part that they
could only be told as by a third person. The following narrative is
drawn from my own experience.
– The Problem of Thor Bridge (1922)
He’s telling you: “The following narrative is
drawn from my own experience.”