The most fascinating question is not "How did a single line in the tax code help trigger a tsunami of mass layoffs?" but how did a single line in the US tax code help trigger a tsunami of mass layoffs in other countries?
You're undoubtedly aware the US has an outsize influence on the sector.
Also this line of argument rests on the idea that the downturn is exclusive to Section 174, but it is not. Raising interest rates across the world are a major factor.