I disagree. There are objective measures for wellbeing...
You've got health measures like life expectancy, infant / maternal mortality, disability adjusted life years, BMI, cortesol, blood pressure, suicide rates, etc. Economic ones like labor market participation, un[der]employment, poverty rates, gini coefficients. Societal ones like crime rates, trust levels, civic participation, environmental metric, public transit accessibility, international test scores, human rights, marriage and actual vs wanted fertility rates. The list goes on. There are countless measures, just few that economists genuinely value.