I'd like to offer a differing perspective. Let's say you have a company that makes shoes. You attract investors by growing steadily at 3% a year. At some point, the market becomes crowded or monopolized such that you can no longer grow at 3% by attracting new customers or creating new products. So you start to increase profit by reducing your margins-- using worse materials and worse construction methods. You use planned obsolescence to increase the number of times customers have to buy your products.

Ask yourself, once this inflection point is reached and quality is no longer increasing, does a growth economy make sense? At this terminal stage of economic growth there is an increase in negative externalities in the pursuit of ever-diminishing profits. Much more waste as the shoes are built with worse and worse materials. More exploitation in an attempt to reduce labor costs. Do you think that over the last 30 years, shoes have increased in quality relative to the profit margins of these companies? If the answer is no, then it means we need to figure out a way to deal with terminal-stage industries.

Sure, there are people advocating for everyone to go live like the Amish, but to me degrowth means that if an industry can no longer achieve growth through innovation or increases in productivity, we should acknowledge that that industry has peaked, and not try to squeeze every last dollar out of it through exploitation or waste.

https://en.wikipedia.org/wiki/Diminishing_returns