Maybe you should try it sometime. Only then you'll find for sure if it works and makes a difference for you, instead of whatever an infomercial or study can tell you.
I've done targeted abs exercise for years, then I stopped, and I literally didn't see any difference.
And more broadly, there are countless fitness systems and ideas out there, you got to apply some critical thinking in deciding which one to pursue.
It's still important to evaluate what you're doing, because we all get those things right from time to time, but before I change my routine I try to ask myself -
Why am I doing this?
What am I trying to get out of this?
What "holes" in my current program am is this going to plug?
And maybe most importantly, how do I evaluate the program's success?
Though generally, I kinda stay clear of programs that goes against my understanding of physiology.