I think the error is in saying "Just 1%", which IMHO is more than would be allocated to bitcoin even at it's prime.

If you have an offshore account you have some wealth. You won't be putting a large % of your cash into bitcoin. Let's say you'd be ok with 3% of your offshore wealth in bitcoin.

Then, assume that only 2% of offshore accounts would actually do so. 2% is a reasonable adoption level.

So now you have 3% of 2% of offshore wealth in bitcoin, which is 0.06% of that 30 trillion dollars. That would be about $168k/BTC.

You can revise what you feel is more realistic, but your equation should account for (level of adoption %) x (% allocation in bitcoin given adoption).