Why can’t other interests, such as labour interests, also bait-and-switch?

Here's my conjecture: doing so is not in the interests of labour. So to the extent that labour has power, it would tend to act differently.

They CAN, but capital interests ARE. Speculation: labour interests care about making enough money to get by, while capital interests care about making maximum money and are therefore insatiable.

What makes you think most labour are interested in “getting by”?

In my experience, they aren’t.

How often do you ask your boss for a raise or go job hunting?

1. When your money's running low or your job feels shitty, or

2. Constantly whenever you think you can get a raise or a better job

I don’t see how that is relevant? Switching job is a fairly painful process. Doesn’t mean I’m not in it for the money.