Bitcoin didn't tank. It experienced a speculative bubble and the bubble popped. How much is Bitcoin worth? It isn't. It has value in it's utility as a medium exchange in the scenarios I mentioned above. Beanie Babies were a fun toy, then a speculative bubble worth a fortune, and then a fun toy again. You'd have to be a gambler or an idiot to risk money you can't afford to lose speculating on the value of anything.

Regardless, the current price of Bitcoin in USD, is entirely irrelevant to any of my arguments.

Of course it's "kept afloat by it's investors". Literally everything is. The USD is backed by faith that the US pays it's debts. Anyone who buys that debt is an investor. If foreign nations stopped buying US debt the US economy would collapse.