Yeah man it's crazy you don'y always notice hi-hats until they aren't there. A producer friend of mine that knows way more about engineering and sounds told me too that Preemo switched his beatmaking hardware / sampler a while back, and that the type of MPC he switched to sounds thinner and less warm/thick/full than his previous machine.
And that could be another reason, because I literally feel like Preemo isn't doing anything that different than what he did in the 00's or even the 10's, and yet his beats just don't sound as soulful and lifelike. They sound more sterile, and not even the sample choices or whatever. Just the actual mix or the sound itself. I think he switched sound engineers as well.
It's weird. I can't put my finger in it. Same type samples. Same type drums. Same type sample chops and loops. Same formula, but the final product doesn't sound nearly the same.