San Francisco Fed Head: “We don’t have a really good understanding of why it’s been so difficult to get inflation back up”

This is from January 3 but is troubling enough that we're linking. If you really think about it, nobody knows anything.
From Reuters:
Fed may need new approach to boost inflation, Daly says

The Federal Reserve could find itself fighting too-low inflation for years to come, San Francisco Federal Reserve President Mary Daly said on Friday, and may need a new policy framework to lift inflation back up to the Fed’s 2% goal. 

“We don’t have a really good understanding of why it’s been so difficult to get inflation back up,” Daly said at the annual American Economics Association meeting in San Diego.

But with global growth slowing and the populations of most advanced economies aging, Daly said, “this new ‘fighting inflation from below’ is going to be with us, I would argue, for a longer period of time than just a few years.”

As a result, she said, “a new policy framework will likely be required” to boost inflation...

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