If I receive 200 resumes and 30% of them are picture perfect - Sorry, I can’t interview or even screen everyone. The resume with unexplained gaps isn’t getting sorted into the top of the pile simply because I have to be aggressive with filtering.
On the other hand, if I’m hiring for a difficult position at a less popular company and I’m only getting 1 or 2 okay resumes per week, I’ll take the time to screen resumes with gaps as long as everything else looks fine.
You have to understand that a lot of hiring managers simply couldn’t screen/interview everyone even if they wanted to. For those jobs, having unexplained gaps in an otherwise average resume could be the negative signal that moves you slightly down bellow the threshold.
But for a lot of average jobs: No, it doesn’t actually matter that much.