I'll point out that I've probably got somewhere around 2 hours of podcast content covering this between Once Bitten 514 and Illegitimate Scholar 074. I do specifically mention World in Peril and Chan Thomas's book on those shows and my presentation draws heavily from both of those sources.

To your question specifically:

1. I didn't care about anything in it other than chapters 27-30. I read chapters 26-31 just to make sure and yeah, I found the information in chapters 26 and 31 to be generally insignificant in the grand scheme of things.

2. Narratively, it makes sense. Wright brothers @ Kitty Hawk, WW1, WW2 more prominently featuring air forces, WW2 ends...now what do we do with all these planes we have and crews to pilot them? Let's explore and hone our understanding of the world. Their choice was rather consistent with Boyd's OODA loop that he conceptualized in the mid 50s in Korea as a pilot.

3. All research should be critically examined with an open mind guarded by robust discernment. That said, when scientists in academia get things wrong, the set of implications don't typically include the reordering of the global power dynamic. When scientists in the military get things wrong, the reordering of the global power dynamic is precisely at stake. That said, military scientists can be wrong but I would tend to expect that they would tend to be right given the stakes.

4. Removing the "life or death" stakes from the equation, military research is also likely to be much better funded given the existence of the military industrial complex and the money printer's existence.

5. The information provided in World in Peril is validated by a number of other sources. Many of those other sources are listed in my OP above.

6. Mechanically, the hypothesis offered in World in Peril, by Hapgood, by Thomas, etc. makes sense and there are viable hypotheses on how it all works. Thomas talks about the work of Nobel laureate Hannes Alfven who studied agitated mercury under varying magnetic field conditions. Thomas believed that the asthenosphere may behave similarly to the mercury in Alfven's experiments during the peak of the geomagnetic excursion events.

7. Speaking more generally of the whole "Earth crust decoupling hypothesis", it makes a lot of sense to me at a number of levels. It makes sense of a lot of flood myths. It makes sense of punctuated equilibrium and its correlation to stratigraphy. It makes sense of many, many Earthly mysteries.

It takes some getting used to, that's for sure.

The language it contains was meant to maximize understanding of nuance so it's not necessarily flowery prose or easy to read.

The material itself doesn't take too long to get through.

After contending with the vocabulary, trying to piece together the cosmological perspective that it offers is the first big challenge.

That's a big challenge because to make sense of it requires a lot of other research. I'm just now in my "junior year" of studying that material and, at this point, I think if I made my research my full time job, your 7 year estimate is in the range of reality. I could imagine it taking me that long to read through it all, digest it, distill insights, and write about it all.