The ghosting is sending a message to people who value money over people. That to me is the undercurrent theme of all this. That is why it is a trend. The companies are not "people" they are entities and the managers are simply lever pulling proxies for the company.
They’re the ones who get yelled at by the customers for the crappy service and upper management for not being able to find someone to come in on zero notice.
I can guarantee that the one place the message doesn’t go is upper management in corporate.
This why a trend where labor is unreliable (in the old days it was a strike) will get people's attention.
This has very little to do with whether someone actually comes into work and everything to do with what they say or don't say.