Matter-of-fact way - meaning

“I could easily fill a book, of cases where men plodding along in a matter-of-fact way,” i could not understand " matter-of-fact way" in this sentence , anyone can help me ?

The dictionary says, “adhering strictly to fact; not imaginative; prosaic; dry; commonplace” but it does seem ambiguous.

I found the context of the sentence:

“”“”…A man by one supreme effort of the will may change his whole career and almost accomplish miracles. You may be that man. You can be if you Will to be, for Will can find a way or make one.
I could easily fill a book, of cases where men plodding along in a matter-of-fact way, were all at once aroused and as if awakening from a slumber they developed the possibilities within them and from that time on were different persons. “”“”"

What the author means is these men go about their day aka “plodding along” thinking in terms they are used to, commonplace/ordinary/factual terms, ‘adhering strictly to fact; not imaginative; prosaic; dry; commonplace.’ They are not imagining more possibilities for themselves. These men awake from this matter of fact, non-ambitious and stagnant mentality into a new destiny for themselves: a new path/way for their future with more “possibilities.” Possibilities are not facts until they happen/ are manifested.

I tried. It’s really an ambiguous word here and it’s not used often.

In english, we say it most often in the following context (in conversation):

"As a matter of fact, I think I am ready to take the test, I know the material. "

“As a matter of fact, the sky is not blue it just looks blue and it can be proven scientifically.”

As a matter of fact, you can replace this with “actually” and “indeed.”

But anyways, the author of the original context is using it sort of as an adjective to describe the way they think and act. “A matter-of-fact way.”