Something has indeed dampened America’s economic dynamism. Startups are rarer, labour is less mobile and fewer people switch jobs than they did three decades ago.

It's not regulations. Consumer credit. New businesses are built on cheap credit, and there's none to be had. Interest rates are through the roof, compared to before the housing crunch. Until you relax that noose, innovation at the lower echelons of the economy is dead as that squirrel on the road you drove by the other day. Ties people to place like wearing a cinderblock while trying to swim laps.