I guess it’s because it would be hard to keep it updated. A review about the movie Inception is relevant today and will be relevant in 10 years. A review about the iPhone N will only be relevant for a short period of time.
Hmmm, and yet early reviews of The Birth of a Nation called it "a triumph".
To be fair those reviews are of interest today, just as the evolution of reviews of that work since are of interest.
In the same manner tech Historians (there are such beasts) will find reviews of various releases of historic tech to be of interest, just as here on HN there's interest in old articles about the performance of BBC Micros, ACORN Achimedes, Commodore 64's, etc.
