means testing is expensive and requires its own bureaucracy.
compensation for capitalism's natural rate of unemployment is based on market based metrics not means testing.
Quitting a job and not looking for another is not part of the natural rate of unemployment.
Means testing is not expensive. You fill out a form listing your income and assets. Most are never verified. If it turns out that you lied on the form, you are prosecuted. The welfare system does not search bank records ect. They have you fill out forms, which they file.
And if you think open-ended unemployment compensation when you are not looking for a job, would not add a mean test, you are laughably wrong.