I'd argue that's a very good reason to have backup options. Remember that looking for a job does not commit you to leaving your current one unless you find something better.
From the employee side, I have no way of knowing whether I've actually found something better. It could be that I've just found a company that interviews well or that got lucky enough to avoid putting foot in mouth long enough to get me out the door.
If I'm in a company that's good enough and am not sure I'll be able to land a job six months from now, it makes very little sense for me to even start looking because I know that any new job I find might be a lemon, even if it looks better during the interviews.
Markets, even markets for lemons, are frequently in non-equilibrium states. That can happen because actors have imperfect information, because underlying conditions have changed, because some actors are new to the market and haven't settled to equilibrium yet, because people have personal beliefs that override market-rational behavior, because market actors are simply bad at their jobs, or any number of other reasons. Far more information-perfect, rational, and optimized markets than hiring frequently show inefficient behavior in practice.
Yes, there are market pressures that tend to remove good candidates and good jobs from the market, and that incentivize both sides to pretend they're better than they are. But a tendency is only a tendency, and not a guarantee, and incentives can be missed or ignored or defied or failed in implementation. A bad company might be incentivized to lie to you, but they have to be self-aware that they suck (a trait terrible companies very frequently fail at) and capable of implementing the deception, among other things. And that means that your impressions when you speak to them do carry meaningful signal that should shift your beliefs about them.
A new job might be a lemon. But it also might not. You don't need to be certain that it isn't; you just need to be sure enough that the expected value of taking the new job, minus whatever risk discounting you're choosing to use, (minus the cost of searching for one), is greater than the expected value of staying in your current job.
Agreed. And what I'm saying is that people aren't looking because the job interview process provides little enough information that the expected value of job hopping right now is very unlikely to exceed the expected value of staying put unless they're already in a bad situation. The time spent fielding phone screens and interviews isn't worth it if you already know that even a seemingly dream job wouldn't be worth the risk right now.
In another, more certain environment with lower risk of long-term unemployment the calculus is different, but right now sticking with the devil you know is for most of us the most rational move until the layoffs slow down.