You are leaving out violent death. And even though the possibility of that has been lowering drastically over the centuries, it is not guaranteed that this trend continues, especially if population growth accelerates because lack of natural death.
But you are probably right about how technology will advance, and how this problem may be left behind by updating the whole network.
Still, in theory at least, we don’t have stable amount of available coins, but a constantly diminishing resource. I’m not sure if hoarding + dying rich in a private submarine 
can have any effect short term.