As a fellow fountain-pen enthusiast, I highly doubt this idea that the pen (and especially the nib) becomes "tuned" to your writing. I think it's either [a] placebo effect or [b] the other way around---the hand becomes "tuned" to the pen---or [c] it's more about the other parts of the pen (e.g., body, feed), and rarely, if ever at all, the nib.
> This is a very hard alloy engineered to resist wear and tear.
> As the user writes, this tipping material starts to get polished.
"Polish" is making a surface more even than before either by [a] filling it in with substance so that the depressions in the surface becomes level with the peaks or [b] filing away (i.e., introducing wear) at the surface so that the peaks become level with the depressions.
Either way, I don't see how it can be achieved with writing. Paper and ink doesn't have anything that can achieve [a] nor is it enough to achieve [b]---even over time---otherwise the nib isn't made of alloy that can resist wear and tear.
I'm prepared to wager that a well-used but well-cared for nib isn't gonna exhibit a more polished angle. It could tarnish. It could build-up a patina. Maybe it could have some chemical residues from previous inks. But to have a significant and highly-localized deviation from when it was brand-new, I highly doubt it.
Another part of my hypothesis is that you don't actually keep the pen at the same angle everytime you write. You still produce the same(ish) handwriting but writing angle is easily affected by external factors. In other words, the writer compensates for these external factors subconsciously in order to produce the same handwriting. E.g., I write differently on my journal vs. if I'm filling out a form. I write differently when I'm jotting down notes in a meeting vs. something more deliberate. I might adjust angles if the paper has a different texture, or if the ink isn't drying as quickly. I would write differently on my desk at home vs. a hotel room desk. Heck, I write differently at the start, middle, and end of a journal.
I'm just saying this because I think people could stress over fountain pens over what is basically superstition and there's already plenty to think of when using fountain pens. It won't change your pen's "attunement" if you lend it for friends to try occasionally. Conversely, don't be afraid to give second-hand pens a try just because the previous owner's writing style might be too different from yours.