I agree, given what we know, Fred "should" have been able to find Howland. But he didn't. That is a fact, so something must have gone terribly wrong, and it is hard to know exactly what. Whatever it was, it is outside the norm, so trying to apply "norms" to this situation - search patterns, logical navigational solutions, "would have" statements - isn't going to solve it because they didn't get there, we have to look outside the norms to something unexpected.
Simply running out of gas as Gary would have us believe, is certainly one thing that could have gone wrong for them.
However, let's put it in context with other events we know happened.
We know that there were many post loss radio signals that were considered credible at the time, enough so that the Navy based their entire initial search on them. If only one of the receptions was authentic, she had to be on land somewhere. The Navy decided to go "search" the land and that was the initial tasking of their search.
We know that there was the skeleton of a castaway found on Niku with items, that would indicate that they were not a Pacific islander, that it looks like that castaway had a surplus US Navy sextant of the type Noonan liked to have with him as a back up, and that Gallager and the higher ups in the PISS system suspected (at least for a while) the castaway of being Mrs. Putnam.
The forensic analysis of those bones indicates a likelihood of being a european female of stature similar to AE.
There is a body of island lore about an aircraft wreck being there before the colonists arrived in 1930.
Apparent pre war aircraft material has been found there that is at least similar in nature to what we'd expect of the Electra parts.
The stuff at the 7 site, Etc.
So, is initiating an expanding square search pattern and running out of gas the simplest answer given the context of some of the other things we know happened? I think not.
None of these things are proven to be conclusively related to AE's disappearance, but they fit a hypotheses - an unproven thing - that TIGHAR has developed in order to try to understand all these oddities. They do not fit with the hypothesis that she was flying an expanding square search and ran out of gas.
I think of it like a crime scene. There are a lot of broken bits of evidence, some eyewitness accounts, rumors, odd stuff that may not initially make sense or seem related. As the investigators of that crime scene, our job is to try to filter the important stuff, find out how things are related to each other, and integrate what's left into a coherent story of how the crime was committed and see if you can prove your hypotheses. Right now we've got a pretty interesting story built around the evidence, but we're still trying to get the confession and close the case. Hopefully this July will be the big break in the case.
Crashed and sank leaves a lot on the table (or swept under the rug?) that still needs to be explained.
Just my 2 cents.
amck