The real answer is that 20 year olds are not buying houses, which is depressing the housing market anywhere that is not in California or New York. With these people not buying houses, they are not buying furniture either. And they are buying used cars, not new, if they are buying cars at all. (Car ownership of 20 somethings is the lowest of all age groups in the US.) And if you are living in an apartment, you are not buying appliances either. And with limited living space, you are probably not buying too many consumer goods as you don't have a place to put them.

Durable goods are a huge part of the economy. Those manufacturing jobs tend to be better paid and have better benefits than service sector jobs for non-college graduates. If this generation gets into the habit of not buying things, then there will be layoffs and other downsizing which will further stagnate the economy. This has been written about by baby boomers who created this fiasco, and of course blamed millennials for being cheap/lazy/entitled etc. More people will be looking at trades instead of college and maybe that bubble will pop; there are signs this is beginning and more signs here