Over the years, Bitcoin has proven itself to be a powerful asset with a predictable supply that can be transferred quickly and instantly with low fees on the Lightning network.
Despite deflationary deficits, there is strong demand for the US dollar. Having lost 90% of its purchasing power since the 1950s, it remains an attractive store of value and unit of account. In times of thin profit margins, in a world where goods, rents and wages are priced in dollars, going 100% to Bitcoin is risky.
The world currently chooses the dollar as the global reserve currency. As long as bitcoin remains highly volatile, it is less attractive than the dollar to businesses and individuals in many situations, especially in places where instant conversion is cumbersome and expensive.