That's the thing, they CAN, they just cheap out.
Back in 2011 Synaptics put out a video showing great PC trackpads that were honestly equal to those in MacBooks. That said, working at Best Buy the last two years I've been disgusted by the crap trackpads that companies put out. Clearly they are there to cut costs, but even setting up the machines became a major frustration as companies add textures to their trackpads and include crappy buttons, or even worse if the entire pad is a button they rock terribly and constantly get false clicks. It's beyond me why someone would put a texture on a trackpad when all it does is get skin oils on it instantly and become stuttery as fingers jump off the surface when scrolling.
It's not that there aren't good PC trackpads out there, its just that for the majority of models the venders simply don't give a damn.