Why do some essay writers just get it while others feel stuck in mediocrity?

I’ve been freelancing essays for a couple years now, mostly for college students at NYU and Stanford, and I keep wondering—what’s the actual difference between those top-tier essay writers who can make any topic sound brilliant and the rest of us grinding through drafts that just feel “fine”? I’m not talking about grammar or MLA. I mean that deeper thing. That invisible click when a sentence just lands. Is it experience, personality, or something they can’t teach you on YouTube?