You can convince bond buyers to endure negative real rates for a while, but not forever.

Used to be there were capital controls. You couldn't easily move money from one country to another. That's problematic in same ways. But gives central banks much better control. We got convinced to get rid of capital controls. But that also means central banks have less power. Open trade makes it worse.

Like in the 80's the Fed was keeping rates high. The Japanese were keeping rates low for businesses. That totally wiped out mid west manufacturing.