That's assuming the chance of each happening is 50/50. And it also depends on your risk appetite. If you have the chance at infinity money with a 1% chance risk of losing it all would you take the gamble? What about a 2% chance? 3%?

It also doesn't take into account conviction and fundamental value.

If I'm being honest, at this stage considering the amount of institutional, corporate, and high net worth value is in Bitcoin, i think the risk of Bitcoin going to zero is significantly less than 1%.

But going back to your specific question, you ask if there is a valid case for owning too much bitcoin? Nah. If it goes to infinity, you'll never own enough. If it goes to zero than owning ANY bitcoin is too much. I believe it's a near zero chance bitcoin goes to zero so based off that logic, I can never have enough bitcoin.