CPI is a joke, they do something called hedonic adjustments to things like tech products etc. It's completely subjective and BS. Technology is deflationary, things should get cheaper because we go after producing them in creative ways one demand is high. CPI is absurd, it only perpetuates consumerism and punishes savers. We product 2x the food society consumes - mostly wasted away, just with some supply chain efficie…
More or less the author argues that stable nominal spending, ie a constant level of nominal GDP, is pretty much ideal. And would lead to falling prices as you suggest.
If you replace constant level with 'target a level of nominal GDP that rises 4% every year' you have pretty mainstream position.
Inflation measures are indeed somewhat subject. Nominal GDP has less suggement calls.
(It's still useful to try and measure inflation. But perhaps it should not be a policy target.)