I am skeptical of a causal relationship here. I think it may be more to do with a different but simple phenomenon: the growth and maturation of countries. Whe

I am skeptical of a causal relationship here. I think it may be more to do with a different but simple phenomenon: the growth and maturation of countries. When a people/country are starting out "from scratch" with little material wealth, of course most of their economic growth are focused on material advances -- getting people to produce more, make technological innovations, infrastructural gains. Postwar USA (and Europe) people's economic activity was just to build up society. (broad strokes of course) As a country gets older and more mature, and its material needs are reaching 90+% satisfied (by some subjective measure) then what happens? People have wealth, interests, commercial activites, and they start disputing with each other over it. Legal activity increases while primary production activity no longer dominates an economy. So naturally, you observe that legal/professional services increase and of course at some point you'll experience a flattening or decrease of raw economic growth as a country can't sustain 10% growth every year. Then you think "oh, the lawyers caused this". But that's not interpreting the effect correctly. I would wager you'd see an increase in the number of doctors and their economic activity, or artists, or musicians, etc. too.