If everyone were to quickly jump on board with minimal consumption it would certainly disrupt the market and cause a lot of companies to lose business... but there would also be some winners. Home Depots, thrift shops and Trader Joes/Costco/bike shops would expand, replacing all the Starbucks.
You'll find that the economies in 2nd world countries more reflect the "mustachian" way of life, although there would also be a lot more capital floating around for business investments. Corporations will still be profitable, and still control the means of production, so you might see them invest the capital to reduce production costs even more. Thinking robots that churn out affordable products in low volumes, or perhaps on demand. Things would be designed so that they could be re-used and repaired and replacement parts for common items would proliferate. New companies would rise up to cater to a more frugal and changing market.
The upheaval would make it wise to change our standard "whole market index" investment strategy since with the assumption of less consumption you could predict certain market winners and losers.