I doubt that the majority of people who would take on a second job or "side hustle" would be so affluent because of it that they would raise the standard of living. Given all the people I know who have worked second jobs, the "choice" to do so has come from them needing more money to make ends meet or to provide for their families, all while dreaming of being able to spend some time with the families they are providing for, as opposed to being in traffic driving from one job to another or in another meeting where they are expected to talk once for 5 minutes.

The people in the world working 2 jobs don't tend to be affluent because of it. There are exceptions among the 3-letter elites, such as Jack Dorsey and his multiple CEO-ships, but those people /already/ represent a standard of living that is all but unachievable for the rest of us.