Does the UAW have that much wealth? Or is this a childish bluff, like cutting off your nose to spite your face?

The UAW is not paying the workers. They are receiving pay from the manufacturers as part of their contract. This is called sub-pay. The UAW only pays workers when they are on strike, and it is not nearly as much as their hourly wages.

The UAW workers wo not get anywhere near what they are making now. Most of the money they get at layoff comes from the manufacturers. And if they declare bankruptcy the union will get virtually nothing from them. And the Unions have been investing their wealth over the years. With the recent market downturn some of those stocks are tanked. So you can kiss that money goodbye. And if push comes to shove do not think for a minute that the Union executives wo not screw the workers too.