You seem to forget that a lot of audiophile fuses, such as those from QSA, Russ Andrews, MCRU and others, are mass-produced $0.30 fuses that have been treated somehow and repackaged.
Some like Russ Andrews and MCRU are honest as to what they do, usually just replating the caps, and they are cheap - under $10.
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Others like QSA are evasive, relabel the fuses (illegal in the UK) and their other claims do dot withstand any scrutiny. They are expensive to hugely expensive.
Your are making a false equivalence between fuses, which the vast majority of audiophiles consider a non-issue, and things like speaker placement, which all audiophiles know is an issue, and placement often determines speaker choice. My speakers were positioned by my Wilson dealer and haven't moved since.
When I stream music there are 7 fuses in play, besides the sealed ones, that's a lot of possible combinations (49?). Life I too short. If fuses are directional, and act as a choke, surely it could be measured rather than testing 49 fuse direction combinations.
You can't make a solid copper fuse because copper's melting point is over 1,000 C. I presume that is why fuse wire is often made of tin-plated copper. The caps are mostly copper, because they are mostly brass, which is mostly copper, plated with silver or nickel, it seems because those metals are non-corrosive. Fuses of this design cost $0.30 and are made to far better tolerances than could ever be made by an audiophile fuse manufacturer.