Theoretically economics could be about "utility", but in practice it's too subjective to measure what different humans value so we measure transactions because

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.