Her apparent commitment to privacy only adds to her appeal, IMO. However it may also prevent her from earning more. Given her modest popularity, I don't think she is making a lot of money nowadays (Mihiro was a case os rare success!). However she seems to be happy with things as they are now.
Differently from you, and although I don't have statistical data, I think she was one of the most popular IdeaPocket girls at the time and could have continued working for that studio for a long time more. Her sudden and unannounced retirement seems to have been due to private life reasons (probably a relationship) and not for lack of work. There is an outdated Facebook page that seems legitimate where she says to be living in Canada. The page has been inactive for years though.
The case of Akiho Yoshizawa, which you mention, offers an interesting comparison. Both she and Sarasa were born in 1984. Akiho however seems to continue doing more interesting work. I say this based just in the covers of Akiho's videos, which I don't watch since I don't find her attractive. This raises a few questions in my mind: Could Sarasa find a different line of JAV work if she wanted to? Is she with Attackers just because she has no better option? Does she like the kind of story-line videos Attackers do?
Anyway, it is somewhat remarkable that she has been with Attackers for so long. It means that, despite her seemingly limited popularity, her work is still profitable enough for the studio. IMO, her current career with Attackers has some resemblance with the career she had with IP: in both cases she stayed with the studio a long time, doing monthly and somewhat repetitive videos, without seeking a different and more ambitious professional stage, although this seemed/seems to be within her grasp given not only her incredible beauty but also her acting skills. I mean, she has all that it takes to go higher in "life" (looks, acting skills, lack of inhibition, apparent willingness to do whatever the director asks) but she doesn't seem to have the ambition to do it.
Akiho works for 2 studios and like yui hatano, she got a decent following in china, Taiwan, and hk because she looks like a local celebrity, which grant her more opportunity to film minor commercials, movies, and events there in the last decade. Like rio chin job, she got some enhancement to her face noticeably her eyes. Some say she got a minor implant, but not as obvious as tsukasa Aoi. Sarasa hiatus and change of name did weaken her status and career especially with the rise of mikami, shoko, and momo alike each year. She doesn't seem that ambitious like using av to get in to variety, singing, or acting like others. Btw mihiro was popular, but she was always like the second tier when there's rio, sora, Maria Ozawa, and yui Aida during her career. Akiho done well for the last 15 Years. She beats out mihiro, sora, and Maria who all started around the same time, but retired in 2010. She's filming av twice as long as them and manage to maintain her status.
Attackers is the sister company of ideapocket and I forgot which spins off from which. I think ideapocket broke out from attackers because they want to compete with s1, maxa, and alice Japan etc with new debuts aka teen angel goddess series. Something akin to those chobit and video girl ai series. However, nowadays ideapocket are doing r*** too. Most ideapocket girls like kijimi, Nozomi Mayu, amami, jessica, and a few more did switch to attackers temporally and permanently, so I don't know if ideapocket wants to clear the older girls from acting young in order to promote new girls like momo sakura and momonogi sakura. I guess age and the decrease in pay made rio, Aino, and miyuki retiring around the same time at the end of 2015. I think amami might have finished all her shoots and are just promoting her movies monthly at events nowadays since some av can be prefilmed like half a year ahead of time like moe's title.