Treasury bonds investors would never put their money into Bitcoin,because they hate risk.
That's the good part about treasury bonds-the guaranteed interest payments,even though the income might be negative due to the inflation rates.
AFAIK,the investors of federal and state bonds in the USA have some kind of tax deductions,so buying and holding such bonds comes with tax benefits.Maybe that's why they are still buying bonds,despite the negative ROI.Anyway,I'm not an expert on that subject.
The belief that many investors will just sell their treasury bonds and decide to buy Bitcoin is just ridiculous.