That's what a lot of people thought in the 2000s, but going by SV salaries the automate or offshore story hasn't really played out! Then again, horses seem to have lost their job in the early 20th century after cars came along, and their population just declined thereafter.
You mean what happens when economy does well enough that it starts overheating which forces an exit from the liquidity trap and turns real interest rates positive? I guess we'll find out soon.
I'm not so sure about that. When the Fed was tapering and starting to raise rates back in 2018, the bond market flashed warning signs in December 2018 with long term rates falling sharply and the yield curve inverting.
Then there's also the market expectations of whether the Fed is willing to go with negative interest rates, which would influence the behavior of bond traders.
Pension funds are required to own some percentage of their assets in govt bonds. Also, many high net worth individuals have a strong preference for safe assets like govt bonds. And then there are speculators who think interest rates will fall and they'll make killing by actively trading on long term bonds. So, there will be buyers. Not all of it is being purchased by central banks.
Central bank buying govt debt or QE is basically just maturity transformation. The Fed / ECB / BoE buys 10 year debt and issues cash which is also a form of govt. debt. IMO, when interest rates are as low as they are, it is foolish to issue short term debt. A lot of people like Martin Wolf and John Cochrane have been calling on govts to take advantage of the low interest rates and issue perpetual (or 50 or 100 year) debt and insulate themselves from sharp increase in inflation or interest rates.