It does. I'm sure some would move, but New York and California maintain high tax rates without turning into ghost towns. To be clear, I'm not arguing the union

It does. I'm sure some would move, but New York and California maintain high tax rates without turning into ghost towns. To be clear, I'm not arguing the union position is correct, just that it's not ridiculous on its face. It's feasibility depends on subtle second order effects like the one you describe, not on raising tax collection to obviously impossible levels.