The powers that be have decided that legitimate but unnecessary concerns about short term modest inflation and illegitimate concerns about runaway inflation necessitate widespread mass unemployment and human suffering, even though it could be fairly easily solved by a big helicopter drop of cash by Ben or by Treasury borrowing at record low interest rates and using that money to, say, build a nice trolley for my neighborhood.
And no one is concerned with "the cost of borrowing by the government." They're concerned about their book, but that's their problem.
