This is not really true:
What other "global reserve currency" can you name that only circulates amongst people running specialised hardware? There isn't one.
Gold and US Treasuries.
I hope you wake up and smell the coffee.
Gold, silver, and copper typically always have some degree of interchangeability in monetary systems, and while mining gold by hand can take a while if you're not lucky, people still do it all the time. And the fact copper is interchangeable and located ALL OVER the place, even less scarce than lead, means it's virtually impossible to corner the copper market or force some type of monopoly over it. Copper acts as sort of an altcoin you mine to get to gold and silver, kind of like how people mine altcoins then dump them for BTC. You can find videos on youtube of amateur smiths mining copper in their back yard and forging copper swords with it.
Since copper actually has some type of intrinsic value and is used all over the place while shitcoins aren't, they can then exchange the copper for some silver, gold, or something else. The big difference in this comparison is that it's obviously not sustainable to keep creating infinite altcoins and constantly changing the algo on them to stop ASICs in order to prevent BTC from being a closed entropy system. It also completely erodes any form of Schelling point for BTC at the same time by the sheer existence of these things.
Furthermore, if I hand you a silver coin, that coin does NOT carry the expensive burden of storing all transaction history of the United States, Philippines, and China. If more than one coin exists (which it would if craptocurrency doesn't die), they would likely also evolve into segregated, regional coins to combat that issue: Chinacoin, US Coin, etc, whose value all reflects their GDP...so basically a bunch of police state coins run by the govt. This leaves the only real valid application of bitcoin as something like a replacement for the SDR in international trade and not something really used in regional trade. But the BIS and IMF will just "print" their own craptocurrency while ignoring bitcoin.
