"Economic growth" can exist on a computer screen completely decoupled from the "real world" and independent of a strong middle class.
IMHO An economically strong middle class is needed to maintain social order. This mitigates the public from hunting and and killing the rich and keeps the public from displacing their social frustrations on to each other and creating riots. Generally its a better existence for everyone.
Historically speaking, I don't feel like the basic way that society fails is by "hunting and killing the rich." I mean, you can MAYBE gloss the communist revolutions of the early 20th Century that way. What else?
IMHO An economically strong middle class is needed to maintain social order. This mitigates the public from hunting and and killing the rich and keeps the public from displacing their social frustrations on to each other and creating riots. Generally its a better existence for everyone.