I never even thought, Bitcoin will be the global reserve currency. Base for that is my knowledge of economics, banking system, debt system, euro-dollar... and how world currency (like usd or eur) has to be somewhat predictable in short and mid-term to be used globally in banking system. Bitcoin was never predictable. It never kept its price the same (or varied max. 7% up or down annually).

Another reason was that it was adopted by big players like BlackRock. And That means it became just like a stock. Traded by central middlemen, bought and sold by big players for a short period, just for making USD money. That means, there is no bigger goal to keep it long term and "fight the system". It was until 2020. But it is no longer decentralized. It's just part of banking system.