4) The US are only 4% of the world population. Bitcoin is a global currency. In addition, as shown above, in the US population crypto has already a high adoption (almost 20% of the population having already bought or held crypto). The potential for future price growths lies mainly outside the US where adoption is often still much lower, even in rich countries in Europe for example.
Very good points overall, but if we want to be honest, for this one, we shouldn't be looking at the share of the global population but rather at the share of the global economy, which, for the US is estimated to be at around 25% (of World's GDP).
A million people from third-world countries, who don't have $10 to spare, even if excited about Bitcoin, will not have as much impact on the price (and that's what most here care about the most) as 1,000 Americans earning $100k or above.
India and China are countries with populations of over 1 billion people, but why can't bitcoin and cryptocurrencies be popular there and why aren't they the paradise of the world's financial industry? Or why is every financial market in the world influenced and dominated by the US market? Although bitcoin is a global currency, it is not a wise idea to rely on population percentage to judge their importance to bitcoin.
For people to be able to invest in bitcoin, they need income, knowledge, awareness…and in terms of all these factors, the US outperforms the rest of the world. We cannot deny their influence and role in the world financial industry, not just bitcoin.