The problem about that dated song is that it mixes three distinct aspects that should be treated separately:

1. Conformist mindset
2. Lack of taste
3. Economy ("ticky-tacky").

The same confusion can be observed in essays and songs about food, still in vogue now. Inevitably, the authors are accused of snobbery, whatever their private financial situation. (According to Wiki, satirist Tom Lehrer described "Little Boxes" as "the most sanctimonious song ever written").

Critical lyricists are best advised to focus on one issue at a time, to mention the possible alternatives in a given (financial) situation, and point out the reasons for their criticism.

Like many lyricists of that decade (and of other decades), MR was neither snobbish nor sanctimonious, but lacked intellectual rigour in this song. Present-day songwriters no longer have the excuse of being pioneers.