If the answer to "am I likely to have to lay this person off soon?" isn't "probably not" then it's good that the company becomes more circumspect in hiring.
The other side of the token is that such a guarantee would help convince more people to accept an offer. I'd personally be hesitant to switch to a less stable job right now, and getting an offer yanked or immediately laid off with minimal severance would be brutal for many. A company providing "we changed our mind" insurance would retire a lot of risk for job seekers - and, if things are going well, it costs them essentially nothing to do.
I've laid out my thinking above, which part was unclear?
Many people taking a job are leaving some other job or passing up on other offers to do so. Imposing a cost on employers when they pull a "whoopsie daisy" and rescind offers or immediately lay off a new employee seems like a reasonable trade off to me.