Firms don't want you to know it, but they are struggling to hire competent IT professionals to an extreme degree. Recruiters are being regularly ghosted (like they used to do to candidates) and turn over is increasing. That's why you see them resulting to tricks like this. One thing to keep in mind is that most managers working today cut their teeth when unemployment was at 10% or so, as such they really only know about bait and switch tactics and the stick. Carrots aren't something that really fits into their mental model.

In short, to anyone reading this. Now is the time to make your move.