Learn English – A metaphor for “ricochet back”

No, There is no imperative to create a new construct here.

When a metaphor ''loses its metaphorical properties'' due to the demise of colloquial meaning of its components, where the meaning remains we call this an idiom. Where the meaning is lost entirely, we call it a dead metaphor. Both of these descriptions are accurate, depending on the time, place and persons from and to which the phrase is spoken or written.

Also I believe the following phrasing manipulates the outcome of the discussion:

'high point [e.g., of a career]'

The above definition includes his very own implied assumption of "high" being strong or successful! It would be far more accurate to simply use the following phrasing in our definition of the zenith of a career:

'strongest or most successful point [e.g., of a career]'

I believe this is simply a discussion of the difference between metaphor and idiom.

In the case of the phrase "Falling in Love" we're really looking at an idiom. Whether or not a person understands this phrase is a combination of 1) whether they've heard that particular idiom, and 2) whether idiom exists in their native paradigm at all (e.g. certain languages have no idioms, and the concept of idiom can be a challenging new one).

However, this is completely separate from the fact that a limber mind can interpret meaning in places where it has not been literally defined. We call this metaphor.

I'll assume you're looking for a simple answer. The simple answer is yes, you're right. The passage in question contains at least one common, garden variety metaphor:

...my memory has a smelltrack...

"Smelltrack" is metaphorically used, and is in a metaphorical construction. The author did not say, for example, "...my memory has a facility like a smelltrack..." or "...my memory recalls smells as if following a smelltrack", and (almost) certainly the author's memory does not have a literal smelltrack.

I did not take the time to analyze the quoted passage thoroughly for other simple metaphors, but many other less simple metaphors do exist in the passage you quoted. Describing those metaphors in detail, however, would begin to complicate the simple answer immediately.

For an example outside the quoted work, but which is illustrative of the issues, consider the word 'metaphor' itself. The word can be regarded as a 'dead metaphor': etymologically, 'metaphor' came from Greek roots meaning 'to bear, carry' and 'along with'. From those roots used metaphorically, the contemporary sense of 'metaphor' derives.

You can see why some people think that language is itself, by nature, metaphorical: all words are popularly supposed to stand for something else. What words 'carry along' with them is presumed (sometimes) to be meaning. In this sense, 'metaphor' in language is inescapable.

Edit: To clarify, in the phrase

my memory has a smelltrack which is like a soundtrack

the simile is "a smelltrack is like a soundtrack", while the metaphor is "memory has a smelltrack". That a simile follows the metaphor does not make the metaphor a simile.