Yeah my first mistake was a simple off by one error: 10% of 10B divided by 100M is 10x not 100x. But looking at it again today I think that 100M number is very sus.

We should hit 10B people in the 2040s. This is a pretty reliable estimate. So 10% self custody in the 2040s puts us at 1B bitcoiners. We currently have ~100M "bitcoin users" but this counts Coinbase accounts, ETF holders, etc. The actual important metric is how many people are using the blockchain. How many self custody users do we have today? Probably closer to 1M actually. So maybe the first 100x figure actually should have been 1000x.

The quantum signature stuff is the most unclear because there are lots of different algorithms to choose from. This fantastic analysis indicates that SPHINCS+ is the frontrunner by a large margin. Those sigs are 100x bigger than current signatures. I estimated 10-100x so this indicates we'll land closer to the top of that range without some big optimizations.

https://conduition.io/cryptography/quantum-hbs/

In any case, you get the idea. We need to scale exponentially and bitcoin just does not do that today.