I think the threat should nevertheless be taken seriously. When the governor of a U.S. state says she wants to shut down a pipeline, you have to take it seriously. We also find ourselves with three cases before the courts. So it's serious.
It's very difficult to assess job losses because the supply chain has flexibility, as you and others have pointed out. So certainly some people are going to try to catch up, either by train, by ship or by other means. At the same time, the supply chain has its limits and it's not necessarily safer than an oil pipeline, as was mentioned earlier.
The case of Line 5 should not be seen as a simple matter of jobs. It is a question of energy security. These are families and businesses that could be deprived of energy. As was mentioned, propane is used extensively for heating in Michigan. Not having access to heating in the winter is pretty serious.
To get back to a comment that was made, in the United States, this issue is often presented as just an economic argument that benefits Canada and does not really benefit the United States. In fact, it's more a question of energy supply for a North American population.