Is it a negligence or an intended avoidance?

I am not talking of MANY. I am talking of ALL.

In talking about English tenses, ALL grammar books are avoiding to talk
about the family of the frequently-used adverbial IN THE PAST XX YEARS (such
as in the past, in the past year, in the past ten months, during the past
two decades, over the past three weeks, for the past few years, etc.)

Is it a negligence or an intended avoidance? Or is it a kind of ritual?

Your opinion is welcome.

Shun
englishtense.com

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