> the US has never had a recession that wasn’t preceded by an inverted yield curve

This is incorrect. Most recessions in the post WW2 period have been preceded by an inversion of the 3m/10y UST curve, but it did not precede a few recessions in the USA during the first half of the 20th century.

[0] http://bonddad.blogspot.com/2011/07/yield-curve-and-pre-ww2-...

Can't you essentially fabricate this statistic by controlling for the amount of time that counts as "before", assuming the inverted curves happen more often than recessions?

I am guessing that "before" means that the inversion persisted until the economy was technically in recession.

Not quite - see https://fred.stlouisfed.org/series/T10Y3M for reference. The grey areas are recessions, and values below 0 are inversions.

To address the GP’s point, the relationship could be fabricated, but the data don’t indicate that that’s happening.

When large number of people are betting there is recession, there will a recession simply because people are collectively contracting their consumption in anticipation.

This doesn't account for recessions before the creation of the Federal Reserve.