whew, glad I wasn't an electrician back then!
or, could you imagine working only with "rigid"? The facility where I work was built in the 30's, and every inch of pipe had to be cut, threaded, reamed, etc...pretty labor intensive. in the Benfield Manual, it says that because of the awkwardness of the first benders for EMT, it didn't come into wide use until the mid-30's.
sorry to float off the thread :-)