First, I must commend you for bravely writing about your experiences and being so forthcoming about your, and others' ("environment"), perception of your standing in the field; especially as a woman, which I think cannot be discounted in this field (even though I am sure you would not want me to acknowledge your gender in this context, and for that I apologise).
Additionally, like others, I first must congratulate you on being able to publish in the area and you should take some solace in that. Your supervisor, and others', attitude towards non-prestigious publications is nothing new, but that hardly excuses it.
In order to better tailor our answer(s) to your needs, I think you should mention two things:
- As a mid-late student, I assume you are not just "PhD student", but a "PhD Candidate", correct?
At this point in your PhD, you should be a candidate. Most supervisors I've known expect their students to be ready for candidacy within about 3 years of starting. If you are a candidate, I would not so-easily consider quitting.
- What do you seek to get out of your PhD? "A job"? Tenure? Employment involving the area you're currently doing research?
If I was to use your assessment as the ground truth, I do not know of tenure is legitimately in the cards (who am I to say this, though?). It is possible, but it may take a lot of sycophancy that you may not find ideal. I think completing your PhD (if you're a candidate) would greatly improve your opportunities to do research in this area, and may even help with getting "a job" in said-area.
If you enjoy the research, maybe you could find a way to be a research assistant without feeling the pressure that is associated with completing your PhD? Surely there are positions available either in industry/academia that can fulfill this desire?
- I know this is going to come off as cliché but "Forget what others think of your work". This is one thing I must give my supervisor a great deal of credit for. He cared about publications and their quality, rather than their venue (he always hoped our work could get in top venues, but always prepared the student to be rejected ["that's the way it goes"]). I feel like that is the same advice I should pass on to you, and to help reinforce it I wanted to share my own story:
In my area (also a subdiscipline of Computing Science), conferences are the predominant medium. However, I found much of my work was actually more journal-oriented. Thus, I naturally diverged from the "herd" even though I was fortunate to be at the opposite-end of the spectrum (if we are being blunt with self/environmental assessments of the student).
Humorously enough, much of my Master's Thesis (I wasn't allowed to "upgrade" to a PhD, even though my work had more than enough meat on the bone. Go figure!) was published in a venue that later-came-to-be-known as "predatory" (Frontiers). I had two publications on the eve of my convocation (both Frontiers). However, anyone who looks at the work-in-question will see the handling editor is an extremely reputable individual in the area, which was a saving grace. This is one way I wanted to demonstrate to you that the venue is not as-important as those who shepherd the work from submission to acceptance.
Indeed, I ended up getting another publication from work undertaken during my masters, in a top tier (applied) statistics journal without any previous work in the area. It turns out the editor did some behind-the-scenes "who is this person?" before deciding to send the work out for review, and when they made that decision it was made clear to me they will publish it if I meet the expectations. It took two reject-with-resubmissions, but it all worked out. So do not discount the words of praise with respect to the quality of your work. Sometimes they do (and in my case: did) help.
I hope this demonstrates that, when it comes to legitimate assessments from a reputable individual in the area, quality will always be the number one ingredient. I had no "prestigious" publications under my belt until they gave me my first (and only [hehe ;)] one.
I think your decision to remain/quit should not focus on "coping" with the denigration of your contributions, as I've unfortunately found this attitude to pervade many "intellectual" areas. Quitting does not seem to be a reasonable option given that you're almost (2/3 in the worst case) done your PhD.
What I think your decision should be based on is: your path to graduation (6 years is what my supervisor TYPICALLY expected, though he himself took 9! [caveat: he is a Stanford PhD, Caltech BSc, and this was 30 years ago. it's a challenging area!]), your anticipated graduation date (have you spoken with your supervisor?), your desired role in the workforce with this education, and whether you enjoy your work in the absence of the prestigious publications.
From a personal perspective, I derive great pleasure from my contributions to the subdiscipline (Frontiers included) because it gave me a sense of belonging.
Some people can "save the field", but those people would probably say that the field saved their life. I know that being able to produce good research and being acknowledged for it (no matter what tier of publication venue), saved my life.
I would hope others in the discipline have a similar feeling. I know my inspirations in the field (two of whom passed far-before their time) felt the same way, and I guess it infected me. I think this should be the crucial ingredient in determining whether you finish your PhD.
Again I commend you for sharing your experience; it is not too different from others', and I hope the ensuing discussion will be helpful to all who come across your question.