"Never again" is a strong opinion in a fragile space. The arguments that you bring on the table are clearly not suited to exclude such a scenario under all or even likely circumstances. Even more, a below 1 Billion scenario is now just 37,701,150+1 USD marketcap away. So say what you really want to say: "TO THE MOON!!".
RE: Why Ethereum's market cap will not drop below 1 Billion ever again.