IMO productivity has been absorbed by getting more for your money in hidden inflation . Eg: today when you buy a phone (and internet access) you get a free encyclopedia (wikipedia), movie theater (youtube), camera, Video recorder, note pad and pen (app), alarm clock, calendar, ... get my drift?
Same with a "home" which is now far more advanced and sq ft per person.
That's where all the productivity gains have gone, the basics of today are more complex than the "complex" things of the past