Theoretically economics could be about "utility", but in practice it's too subjective to measure what different humans value so we measure transactions because those largely use consistent measurable currencies.

It's interesting that economics doesn't usually factor in how much value is created by things that has a transactional value near zero, such as:

  * a housewife maintaining a household,
  * a person who quits work to care for a dependent family member, or
  * open source software.

I'm curious how you know depression is at an all-time high given it has never really been measured before. Do you really believe people in the US are more depressed now than in the early 19th century, say? Consider that people includes Native Americans and African Americans.