This is a gross mischaracterization of what Krugman believes. All of your statements about his ideas are wrong as can be easily verified if you read what he writes. A quote from the first link of a search of his writings that debunks your first claim.
But we won’t always be in this situation — or at least I hope not! Someday the private sector will see enough opportunities to want to invest its savings in plant and equipment, not leave them sitting idle, and the economy will return to more or less full employment without needing deficit spending to keep it there. At that point, money that the government prints won’t just sit there, it will feed inflation, and the government will indeed need to persuade the private sector to make resources available for government use.
And that’s why I don’t accept the idea that deficits are never a problem.
But we won’t always be in this situation — or at least I hope not! Someday the private sector will see enough opportunities to want to invest its savings in plant and equipment, not leave them sitting idle, and the economy will return to more or less full employment without needing deficit spending to keep it there. At that point, money that the government prints won’t just sit there, it will feed inflation, and the government will indeed need to persuade the private sector to make resources available for government use.
And that’s why I don’t accept the idea that deficits are never a problem.
The last sentence is particularly relevant.