In some countries where there are avaliable jobs, we have people working on 1, 2, 3 jobs so for such a person he already have an alternative and can easily switch for a better offer no problem.
What is a problem is when you quite your job, without any alternative, i mean you enrolled yourself into the unemployed academy, also is important to develop some skills amd training, that way when youare out of job, you have something to fall back to.
Ops can you include a link to your quote as a form of reference.
When you search for jobs while being employed, it will lead you to better bargaining positions. You get to avoid the noise of a resume-gap bias, maintain social capital, and continue to have income flowing. I would argue that this can make it easier, not harder, to secure a better role. And it would even be better to stay proactive and use in-job time to upskill or participate in side projects that will ensure continuous growth as you work behind the scenes to find new gigs. Bailing out prior to locking in something is tantamount to income shock or an unemployment black hole. The best thing to do is to remain smart, remain employed, and remain strategic.