Antiquing (as a verb) is a visual affect that is applied to imitate the effects of age. Again, true for all kinds of materials and artifacts.
To the extent that antiquing is done with the sole intent of creating a pleasing appearance and with no regard to the effects aging would actually engender, it fails its implied intent. Whether it succeeds as a pleasing affect, is a matter of opinion and what are fundamentally ephemeral fashions impulses.
The issue of polish has been raised. All polishes (except neutral) have dye in them. To the extent that those dyes are not the same colour as the underlying leather, colour changes are being applied to the shoe rather than being acquired.
Follow the logic...it is undoubtedly true that if you polish a shoe with a neutral cream for years and years (and never clean it) a certain amount of dust , grime, and micro-fine debris will be picked up and accumulate in corners and crevasses.This is part and parcel of patina. Does it look old and like it was an antique? Surely it does, but only as a result of natural processes, not artifice.
If you start with a tan shoe and you polish it with a slightly darker cream/wax for years, that dye is going to alter the colour of the leather. Is it due to natural processes or artifice? Surely logic dictates that the use of a material that is intended to add colour means that it is artifice.
Now take it to its logical extreme...if you start with a green shoe and polish it with red cream, you may get some startling effects but no one could rationally say that they were the result of aging. I don't think anyone could reasonably suggest that this was an acquired patina, either.
So what is it? It can be perversely called "antiquing" but only if you think that a green shoe with red toes looks old.
And the distinction between using a red cream on a green shoe as opposed to using a medium brown polish on a tan shoe is a distinction without meaning.
Shoe painting, tie-dyeing....either/or comes closest to an accurate description in my book as any.
Again, whether these affects/effects are pleasing or in vogue is neither here nor there.
And not really an issue in my comments.