There is no such thing as a race to the bottom.. This is a common trope from people who don't understand economics. Union benefits are zero sum rent extraction, and in the long run, inhibit economic growth and with it broad-based wage growth.

There are professions when skill transfer is problematic, like a railroad engineer, but warehouse worker is not one of them.

It is indeed not frictionless and requires some effort, but it's certainly doable.

You've just explained why this power isn't realistic to invoke. If you're a warehouse worker, can you afford the unemployment time long enough to find another job? Can your family?

In real life most people first secure a new job and then resign from their current position.

To answer your question: no, my family cannot afford me not working for half a year as well. I believe this is the case for most of people not living with parents.