Just my two cents, but I don't think Jacob's case has been abandoned at all. The one long constant stream of thought thread is now divided into categories, so it may feel as though fewer are present. And it seems the number of posters has always fluctuated at various points in time.
Most posters here are invested in a particular person(s) as their perpetrator of choice. The truth is we're all operating under a serious handicap of not knowing all the evidence the authorities have, not knowing what evidence there may have been that is now for whatever reason gone, nor why potential evidence from DR's house is still under wraps after five years. I know the sheriff et al said it was because they are waiting for advancements in technology so it could be a while -- or perhaps never.
Added to this mix is the fact that we have to be careful who we talk about. Apparently we can discuss Vern Seitz because he's no longer among the living (?). Or maybe he was referred to as a POI, I can't remember. I know I have to be careful about the person I am suspicious about because I could be sued. Thus I carry on my research independently in the desperate and probably vain hope that I'll uncover something. Honestly, I have unearthed a few things that raised my eyebrows, none of which I can discuss here and none of which amount to concrete evidence in Jacob's case. My best hope is that one of the relatives of my personal poi will overcome any fears they might have about coming forward. In my opinion, my poi is scary and intimidating. But I digress.
I think it is helpful to stand back from a case on occasion to clear one's mind and perhaps become more open to new ideas. As far as I'm concerned, short of the actual police and FBI etc., Websleuths members have gathered the most comprehensive research (that is not sealed up in the sheriff's office), and expounded upon most if not all of the popular theories more than any other group (that I know of). It is astounding to me to go back and see how long many posters here have been trying to understand and crack open this case. It at once angers, frustrates, saddens but most of all encourages me. I'm angry that we are not able to know any salient details due to the case still being considered "active"; frustrated that the case has stalled, sad that the family and community still have no answers, but, nonetheless, encouraged that people (here) don't give up.
I have not given up either, but at this point I think it's going to take either some kind of misstep on the part of the perpetrator, or, a friend/relative of the perp finding the courage to speak up. Since I'm a believer I'll also throw in divine intervention. Further, we now have a book in our hands (It Can't Happen here) to break down and study.
I pray to God we can get answers while the perpetrator is still alive. I also pray an arrest is made while the Wetterlings are still alive. As an aside, a bunch of cold cases were solved in 2015 -- cases that were decades old, so I remain hopeful. That one piece of concrete evidence we need could be just around the corner -- or it could be years away. There are people who know the perpetrator (whoever he is), who were and are suspicious about him, who may be hoping yet to hear him confess or find something tangible to tie him to the crime. They might be reading this thread now; they may have been reading it from the beginning. They might be praying for the courage to do the right thing. Okay that was more than two cents, but for the record, I'm never giving up on Jacob (or Joshua).