Why nominalize words instead of using them directly as verbs, adverbs or adjectives?


My question is focused particularly on verbs ending in て form nominalised with
の and adverbs ending in く also nominalised with の:

> かねての instead of かねる
>
> 近くの instead of 近くある/近い

My understanding of nouns (no-adjectives) made from the て form of verbs is
that they mean "after-having-done" as noun qualifier. For example, 兼ねる means
"to do two things at the same time", so 兼ねて/予て would mean "after doing/having
done something at the same time".

I think this is similar to how な is used for nouns. (Original meaning: I
thought the function of の was similar to な.)

On the other hand, I don't understand the need for くの. I know that words such
as 近く are used as nouns, and I also understand that 近い can't be used at the
beginning of a sentence, as discussed in [this goo
article](https://oshiete.goo.ne.jp/qa/2848163.html) (the reason why I talked
about relational nouns was because 1. One of the answers for the question
found in the goo article talked about の nominalised nouns usually having a
trait of range in them, like long to short, etc. However, I am not sure nor do
I think that relational nouns are the proper word to describe them) However,
why not simply using 近い directly attached to a noun instead of 近くの? Why does
近い need to become 近く?

In short, why do some verbs or adjectives have and need their noun forms that
come from their continuative form (て) or adverbial form (く)? Why do they need
to become [relational nouns](https://en.wikipedia.org/wiki/Relational_noun)?

