Tax: that isn't really true. There are algorithms available that really do clean up video images. Ofcourse, the quality will not be as good as in modern video, but thety sure can enhance the picture!
These algorithms are quite expensive (and may be hard to get) as they are intended for real studio use. There is however software, like Adobe Premiere, with built-in functions to clean up video's. The filters aren't really that good, but perhaps they are sufficient.... maybe you should try them once!