So if 2000 people a year go missing and aren't found again, and there are 40,000 unidentified remains, the math suggests that the missing have been stacking up in the unidentified remains pile, and that would fill the missing person's gap every year for the last 20 years. One might be tempted to assume that 2000 who go missing don't end up in the unidentified remains pile, but if the remains are unidentified, then how do we know? Someone could go missing and turn up 5 or ten years later and end up in the unidentified remains pile and anyone who had previously wondered where they had gone may not know, or for that matter even be around themselves to check. So these numbers suggest that the real number of truly odd cases are very few.
I don't think the numbers are enormous, but I think they are significant enough to warrant attention. Even one case with unexplained elements should be investigated. After all, if you have 1,000 faked photos of a UFO but 1 real one, that doesn't mean the real one is invalidated. And to family members of the missing, I don't think the stats nullify their pain or desire to know where their loved one went.
Also, just because someone ended up in a John or Jane Doe file doesn't mean their case can't be truly odd. In some of these cases, there are no signs of trauma or obvious foul play and if enough time passes then the remains may be scattered and the "crime scene" contaminated. So someone may see a dead person who appears to have died of exposure in the woods and chalk it up to a homeless vagrant or misadventure and throw them on the unidentified list.
I'm also sure there are unreported missing people who could became unidentified remains with no missing persons case to attach to them. A recent case includes Erica Parsons who was reported missing 2 years after she actually disappeared (and only because her brother was angry about being kicked out of the house - as far as I know she has not yet been found):
Erica Parsons, 15, Reported Missing Two Years After She Was Last Seen - The Dreamin Demon
Or the situation with adopted children being given away. While this wasn't an unreported missing persons case, it could certainly have become one if she was killed by her tormentors since chances are no one else would have bothered to check up on her:
Adopted girl says mother forced her to dig her own grave - Investigations
Considering that there are apparently places online people can go to give away adopted children with no official report/mediation, who is to say that some of these kids don't eventually become unidentified remains that are never reported as a missing person? Again these specific cases aren't paranormal or odd, but they illustrate how there are many finer details that must be considered when looking at a broad statistic.
This is pure speculation on my part, but I could also see the way law enforcement handles the discovery overlooking the elements found in the Missing 411 cases, especially in decades-old cases when the handling of crime wasn't as refined as it is now (and when these elements were not known). I have heard many situations where law enforcement downplays the concerns of family members when someone goes missing. They say someone was a runaway or will turn up then we find out the person was murdered. Or they get stuck on a specific theory and work to prove that rather than find out what really happened (I have heard this happen when a spouse/child is killed or missing and they focus on the surviving parent/spouse while precious time passes - in fact I recall at least 1 case in the Missing 411 books where this exact situation happened).
I'm not saying this happens all the time and that every missing person case is somehow paranormal, but this is an example of how the interpretation of law enforcement can govern the direction of the investigation and the conclusion it comes to. This has happened in conventional cases in the past so who's to say it doesn't also happen with unconventional cases?
I could see something like this influencing how an unidentified persons case is handled. They may unintentionally overlook the elements that indicate strangeness because they assume it's just a vagrant or unfortunate hiker and look no further into it once the body is brought in and added to the unidentified remains list. And so family never knows they are there and we never have a chance to compare notes to discover how many really fit into this strange template. And sometimes the data entered into missing persons databases isn't 100% accurate, which could prolong the discovery process or even prevent it. It's just something to consider.
You make a point, but I think general statistics doesn't provide a solution here. And I suspect there are probably more cases than we are aware of because of how they were handled and/or the inability or refusal of people to recognize elements that they have a hard time accepting could be involved. Plus we also have to consider that a general stat is going to cover higher population areas that are more likely to have a greater number of missing persons/remains which could skew the numbers. It would be nice to get those same stats for individual national parks where these disappearances take place, but that information is being curiously withheld - another factor that should raise a few eyebrows.
I should also add that I think in most cases law enforcement does a great job and they have managed to solve some difficult puzzles. There are many skilled, hardworking people who do a job that many wouldn't touch, and they deserve to be commended for that. My comments about L.E.'s handling of remains/missing persons were mostly reflecting on older cases when we weren't as quick to respond to things like missing children (or when such resources weren't readily available in some regions).
Now that we have better technology and quicker response times, it will be interesting (tragically so, though), to see if this helps us get a better perspective on the actual volume of strange disappearances/deaths. That is, of course, if there isn't a cover up effort underway as we have seen hinted at in a few of these cases. Hopefully awareness will lead to more people questioning and paying attention.