Not the total circulation supply because based on the CMC, it's 18.7 million Bitcoin at the moment and it might the rest of 21 million are in locked wallets or lost private key that will never open anymore.

It's impossible to turn out zero value your Bitcoin investment, that will never happen of course.  There's no way to even a 50% loss in your portfolio because Bitcoin was always mattered on the demand and supply, not likely if the whole;e world demand total banning of Bitcoin which is on every dark side compared to Bitcoin adoption which is now we will see that has started in most countries especially in the third world countries.

As long as you will never sell, it's unlikely that you will lose all your money.  If you invested 1 Bitcoin, it will always remain 1 Bitcoin in your wallet.  Considering, no lose at all.