I think my problem is that the people that have little enough imagination that they cannot see what their job might look like after are maybe better replaced?
Fear cuts in before the rational mind can process, and it conditions subsequent actions - including the ability to visualise and appropriately weight potential positive outcomes. You need to apply energy to boot people out of the local minimum they've fallen into so that they can end up in the right place.
It doesn't really matter how well you can imagine your job afterwards, if the powers that be are more likely than not primarily imagining reduced labor costs.
Here is a fun book for you, if you want: "Who Moved my Cheese?"[1] An HR person shared it with me in the dot.com era as things were exploding around us and I found it pretty informative. Basically it seems humans see "bad outcomes" as more likely than "good outcomes". It could be an evolved survival trait or it could just be a tendency to be pessimists, but even WHEN you explain how someone's job will exist/improve/change with the change, they will not actually fully believe you.
For reasons I'm not entirely sure I understand, I tend to be pretty analytic about this sort of thing and until my role started including the need to help people understand change it had not occurred to me that fear would overwhelm some folks rationality. But once you can see it, it is really clear that that is where their head is and the anxiety is consuming them.
In the US where healthcare is tied to employment, the possibility of being replaced can literally be life or death.
Especially with efficiency culture where labor is often the first to be cut in the name of profit.
The fear is perfectly rational because managerial and C levels have made it clear that the person does not matter in the slightest. It would be foolish to outright trust management and is often how people are taken advantage of.