The prevailing consensus is that interest rates and inflation are inversely correlated, so "negative interest rates worked out fine" isn't a rebuttal to that.

How is that true with inflation? Under the exact same scenario but with an inflationary monetary policy, any money you sock under your mattress dwindles down to a fraction of its purchasing power over the course of many decades if it is not invested into a vehicle that generates returns. That could be equities, bonds, housing, or even an interest-bearing savings account. The point is that an inflationary regime incentivizes investments as a means of wealth preservation.