I believe part of the reason is because most yoyos lately have been pretty much the same, they look similar each other, have similar quality, they are becoming more, uh, forgettable. Some do however make something new that leaves good impression, but that is only a small portion.
I feel like in the past there are less release at a given amount of time yet a lot more diversity between each designs, and difference in quality is noticeable.
I used to read reviews quite a lot, but now there is little reason to. Most yoyos released will almost always be good I stopped worrying.
Less people who want reviews, less reviews I guess.