Why does 「（から）というもの」 have a meaning of "recently/since"?


I have given three examples below to illustrate my question. I can't
understand why the expression "というもの” equates to "recently/since".

> この一週間 **というもの** 、忙しくてほとんど寝ていない。
>
> For the / since last week I have been so busy, I have hardly slept.
>
> 結婚して **からというもの** 、映画館で映画を見ていない。
>
> I have not been to the pictures since I got married.
>
> ここしばらく **というもの**...  
>  “Recently for a while now"




According to 日本語表現文型辞典：

For the expression [Noun]というもの such as in the question, if the noun is a time
expression (source: 期間を表す言葉) then it implies that the time period feels long.

Continuing clauses follow after というもの.

When は is appended after というもの、it is more emphatic.




It doesn't so much mean "recently/since", but in these example sentences, the
phrases that というもの is modifying or emphasizing does.

In your first example sentence, what corresponds to "since last week" is
actually the この一週間, and というもの just emphasizes it. The meaning stays the same
if you get rid of it.

> この一週間、忙しくてほとんど寝ていない。

というもの literally translates as "this thing called": と + 言う + 物

Here are a couple other
[examples](http://tangorin.com/examples/%E3%81%A8%E3%81%84%E3%81%86%E3%82%82%E3%81%AE)
of it:

> 馬というものはひじょうに役に立つ。 Horses are useful animals.
>
> それはご都合主義というものだ。 That's opportunism pure and simple.

