Needing only one job is a historical anomaly as a result of an industrial society. Historically, people would have to perform a variety of tasks to provide for oneself.
Furthermore, more than one job de-risks someone's situation just like a consultant with many clients can handle the loss of a single client and not see their income fall to zero.
It's the total hours of paid labor over N jobs that you should look at instead. If you do 60 hours a week at one job or three jobs for 20 hours each, you're doing the same amount of labor with less risk.
The only qualitative difference between one 60 hour job and three 20 hour jobs is the benefits received from working 40+ hours for a single employer, but this isn't an issue with how many jobs you work. It's an issue with an artificial asymptotic condition created by an act of legislation by government.
Every time legislation creates artificial asymptotic conditions, you're going to get actors that optimize around that artificial boundary condition. If you want to avoid the circumstance, you need legislative solutions that are continuous in nature instead of asymptotic.