Well, that is not quite true and quite frankly points out what kind of a bullshit artist Greenspan is. Basically the 1% of the 1920 owned a lot of capital assets like properties, farms, business, shares, jewellry, even what are today vintage auto mobiles and these would all have adjusted to inflation accordingly and they would be exceedingly wealthy based upon today's standards and today's property and business values. So Greenspans statement is 100% total crap.
When you own the means of production, the means of generating wealth you are never poor, until it is stripped away from just after a bloody and ruthless revolution.
What these asshats are alluding to is the truly disposable workforce. When you are no longer of use to psychopathic capitalism you are disposed of, parked in concentration camps for the unemployable, only let out for chain gang style mass labour projects. These are very evil people as they make no mention of reduced working hours with increased pay against productivity gains, more time for leisure and free education, with the contributions to society spread out to take into account automation.
All these fuck heads see, is automation, ahh no expensive work force more profits for me. With no concept of who they are going to sell the shit to, other than that workers must accept significantly reduced status unless their existence is sponsored by an employer. These people are a real and present danger, a threat to humanity.