It is a little rich to simultaneously complain that the article is too long, that it didn't go into enough detail, and that it didn't support your pet theory. Maybe if you'd read the article, you'd find out that not only does the author discuss money as a motivating factor as the first example (precisely because it is popularly hold to be the main motivating factor) but then immediately explain why it was the least important motivating factor for pre-modern societies.

It's also worth mentioning that directly linked from this blog post are several in-depth examinations of historical military systems, including Mongol, broader steppe nomad (note that the Mongols were exceptional), Roman, Carthaginian, Macedonian, Greek, and Gallic specifically covered in depth, and a couple of other cases (e.g., Medieval Europe and Mamluk examples) more covered in passing. The detail you think is lacking can easily be found in those blog posts.

You can also find a nice summary of the different motivating factors at the end, with 21 specific examples distributed among them. Is that not enough for you?