I kinda share the same feeling. As I said in another post several weeks ago, my download is now almost 50% "old" JAV. My last addition to my list is Sakura Kokomi. Easily in my top 5 of best girls of JAV ever. I download HD releases and convert them to SD (to save space but I might take the HD versions back later) and I'm so amazed how awesome her movies are. Of course same thing for Yuma Asami, those girls did very good movies. It's now more difficult to find releases that are that much exciting. For example : Aki Sasaki. Tons of movies come out but in my collection, I didn't find any hot movie since WANZ-555 (still have mixed feelings about it). I have the feeling that now it's more about quantity than quality. Of course there are girls who give me that excitement such as the sadly freshly retired Sakura Kirishima or the newcomers of 2016 like Morino Odori and Maijima Akari. But the big stars don't seem to exist anymore.
same like music, there is a time when we prefer the oldies like The Beatles, ABBA, Everly Brothers, Sinatra, and others
once a while we don't like the new girls, and lost interest to the current stars, but later we'll find or favorites again