As a result anyone with enough old money can parasitise on productive society forever, to the nth generation. And instead of doing so by (at the very least) stimulating the economy through investment, they can do it just by sitting on their mattress full of cash.
Again, why would I participate in an economy where my hard work is of direct benefit to people just sitting on cash?
It's only when money are invested then you have a surplus of things in the economy which deflates the money. By investing, hoarders allow others not-yet-rich people access to capital. Thus, if hoarders want to become richer they will have to make rich others too.
Does it though? I thought we were all addicted to growth? If we continue to have any growth then with a limited cash supply, each unit becomes worth more (deflation).
"By investing, hoarders allow others not-yet-rich people access to capital."
I'm not clear on how you think this works, because (AFAICT) hoarding BTC is just holding on to currency, not any sort of investment?
" Thus, if hoarders want to become richer they will have to make rich others too."
Or they can just sit on it while others do the work and achieve much the same with no risk...
It's a tricky circle, but once you understand it, it all becomes clear.
I find it very common even here on HN that many people fall for this fallacy that money == value.