That's interesting, but even 2k scans of first gen film straight from the camera is far from razor sharp. What they have is probably a 3rd gen release print from the 70s, so 4k is likely not going to look fantastic by today's standards and definitely won't make use of 4k resolution.
The idea is to recreate the experience of watching it when it first came out, not to make it the absolute sharpest version. That it's in 4k is just to better be able to capture even quirks of film grain and so on, not to try to make it seem like a modern digitally captured movie.