I think your expectations are a little high. At 1080p I can almost make out the plate, but it's not "passing" it's a good 50ft in front of you and in the shadow. Extracting a few frames and zooming in with decent photo-manipulation software might be able to enhance that enough to make out the number. But overall that looks like typical 1080p quality to me (given the lens & associated sensor size).
There's the trade-off with dashcams, everyone wants small packages, which means small lenses. And wider fields of view, which translates to that "zoomed back" feel. And, of course, the speed/size/heat limitations recording to SD media. When you combine all that with cost expectations, there's inevitably a barrier to quality. Over time that barrier will shift higher.
But it's okay to complain, because we'd like to hope the camera manufacturers are monitoring "demand" for higher "quality" (resolution, speed, etc). We can hope that one or more will come up with increasingly high-end ones, knowing that some of us will pay the price to get it. I know what I'd classify as the "near-perfect" dashcam, but my gut feel is that'd be at least double the cost of the 750S to get it. :-(