if bitcoin were banned everywhere, why would demand increase? demand from who?
i mean sure, black markets could still exist, but prohibition greatly cuts markets down in size. all institutional investment would cease, mainstream retail investors would jump ship. its utility would be greatly reduced because cheap, legal fiat gateways would be gone and only expensive, black market exchangers would exist. miners couldn't operate in the open, reducing the value of the network's security as hash rate drops.
i don't think bitcoin would die but a million bucks? sounds like crazy talk to me.