> spend their savings on things that are useful (instead of stuffing it in their mattress)

People are literally spending all their money on food and rent, not stuffing it in their mattress. The only ones doing that are the ones on top, hoarding wealth and exploiting their underlings.

> ability to make products people want

Wealthy investors have decided this isn't important, all that's important is cutting costs so they can hoard more wealth, which usually means exporting production out of the country so they can exploit laborers in other countries where they don't have protection through the law. This is why we currently don't have enough masks and rely on foreign countries to produce them for us.

The "world economy" only seems to measure things that make rich people richer, and how effective these things are at doing so.