Some excellent points, Spookdaddy. There are many variables at play in a typical search and rescue operation. Often those searches are conducted in areas that are difficult to operate in at best. The level of competence of the searchers varies a great deal. Resources are allocated with the safety of the participants in mind. It's not unusual for a person (usually a person's remains) to eventually turn up in places no one expected them to be, which may have been searched but not very thoroughly.
I ended up going down a rabbit hole the other day, after re-reading that scathing review of Paulides' books I posted a link to above. The author of that piece (which is not without its own flaws) quoted Paulides thus:
Michelle Vanek disappeared in Colorado and according to Paulides "something catastrophic happened to Michelle Vanek that no one could have probably survived"!
That piqued my interest. The name of the victim did not ring any bells, but being a Coloradan, I thought it would be interesting to see what I thought about Paulides' assessment. What I found was yet another sad story, the result of a series of bad decisions and garden variety blunders. The sort of thing that kills many people every year. The only thing that's mysterious is where Michelle Vanek ended up. She has never been found, but her last known location is in very rugged country that could probably never be searched with any completeness unless you put a good number of troops there for months. We don't need Bigfoot carrying her off in order to make sense of her disappearance.
One of the interesting things about the search for Michelle Vanek is that after a few days, friends, acquaintences and volunteers of all sorts showed up in surprising numbers. It became the biggest search in Colorado history, according to some news outlets. Soon the local sheriff found himself having to spend most of his time and resources ensuring the safety of the searchers. The last thing anyone wanted was for a member of the search party to go missing. That's a very real possibility in that kind of terrain. To give an idea of what the terrain in the area is like, a few years later a man from Chicago disappeared near there. Twenty-one months later, his remains were found near his tent. At his campsite. Searchers had passed within yards of him, though he was probably already dead by that time.
Another interesting thing I found is that Google has really got the 3D thing working amazingly well in some places. Here's a link to the image of the 14,005 foot peak Vanek was climbing when she disappeared. Her last known position was on the ridge just to the south of the marker. If you zoom in on the rocky field to the left, the area that looks like gravel is actually a field of boulders the size of cars. It gets really interesting if you go into 3D mode and have a look around.
Mount of the Holy Cross