The recently-ended strike by the NFL referees illuminates an interesting (if obvious) feature of strikes in general: they only work when comparable substitute labor is not readily available. In the hypothetical pure Keynesian stimulus world, a hole-diggers and -fillers union would have zero clout whatsoever because the next guys in line, the non-union workers, could do exactly what the job required. In the real world recently encountered by the NFL, substitute referees were available but the overwhelming consensus is that they were not the same quality of labor as the refs they replaced. This is why the regular referees won out.
When a large, established American union like the UAW strikes, the situation is not quite the same. It may be the case that they cannot be replaced so easily—I’m not familiar with the technologies and techniques used to produce automobiles, so I couldn’t say for sure. But assume that it’s true. Let’s say the major auto manufacturers brought in non-union labor that was less skilled to keep production running. Producing automobiles of the same quality would be costlier, or they could maintain the same costs and produce lower-quality automobiles. I assume that the regulatory structure in the US means that there is a limit to how low the quality of automobiles could be, and in addition they have shareholders to please so that option is pretty hard to take.
But the major automobile companies are in a very different position: there are substitute products readily available. The auto industries in Japan, Germany, Italy, South Korea, and other countries could pick up the slack during a sustained strike by the UAW. Sure there is Canadian football and there are other sports entirely that American football fans could watch, but these are not close substitutes. [Except for Canadian football, I suppose, but there are only eight teams. Plus the games are hard to get to.]
Overall, the message for fans of the strike method is not to get too excited by this round. It’s hardly generalizable.