What I think is that if bitcoin continue to remain a deflationary coin and if the price continue to rise,
If Bitcoin continues to be deflationary, then I think it won't be the next reserve currency but rather the "preserved" currency

. This way government will act like Bitcoin is an endangered species that is about to go instinct or ultra-rare due to many Bitcoins being lost along the process of history.
Anyway, with the action of the US of not buying Bitcoin but rather making their seized Bitcoin their Bitcoin reserve kill the idea of Government investing money to get BTC. Rather, i believe the government will will just heighten their security and tracking to spot illegal Bitcoin transactions and apprehend the culprits and seize their BTC to make them the country's Bitcoin reserve.
more countries will make it to be part of their reserves. I think it will compete with gold and probably later compete with dollar. Just that time is important, people needs to be patient as this may take years or decades.
I think this is already happening since in my country, one of the congressmen proposed a bill about having a Bitcoin reserve, and probably many country will propose such bills too. I think we just need to wait until this bills are approved or rejected.