Slight OT... but talking about other idols as possible pattern of where Rion is going...
Mizuki Akai's figure (back in the days) was a match for Rion. Perhaps Rion has a slight edge in some undefinable quality, kind of like
a Leiji Matsumoto dreamy woman, Akai is pretty enough, but next to Rion she might look a bit whorish.
What Akai has over Rion is (1) sexual energy, (2) non-sex acting skills, (3) professional altitude. EBOD-280, -313, -363 were some of the best AV ever.
And then ... it's a total mystery to me what happened. Akai disappeared and her reboot Honoka Orihara was nothing like Rion's reboot. Orihara started as an average busty idol, getting the debut on the mid-range label BOBB, made a bunch of solo works that was neither high profile (comparable to EBOD or ABP) nor specialty/kinky/hardcore. Very easy to miss (like I did) unless you were a major Akai fan. And then it went downhill, she start making more and more non-solo vids (each scene performed by a different idol), her name is still on the cover, but seems she couldn't sell a vid all on her own any more. And then her stars fell further still, she's now the (ironic) top star of "amateur" AVs, like HUNTA and Apache, SOD. Of course there are also the uncensored vids under either names.
Actually I am not unhappy with her new vids, she's probably
the top hotties making uncensored vids semi-regularly. Any "amateur" vid starring veteran/professionals are the kind of amateur vids I love best. So it's ok for me. But I can't imagine she's making a lot of money... or maybe she is living a good life, I don't know. But certainly she's become almost invisible, often appearing on DVD covers with a white or black bar obscuring her eyes. (but any fan would recognize her distinctive face and boobs)
So that's a path I wasn't paying attention before: high output but invisible as "fake amateur". There are many idols that sort of fit this pattern but Honoka Orihara is particular obvious since she has almost no visibility in the "mainstream" AV anymore.
Why did Akai/Orihara went the way she did? Is it what she wants? Or it's forced on her? Is it due to her (unwise?) making uncensored vid or uncensored vids was just one of the result, not the cause? Is it because she got a little fat? Or skin not as perfect beautiful any more?