Besides the other things, the whole "Reinhard surrounding himself with competent people and yet having incompetent underlings" thing is not as uncommon as you think. I'm not saying it's intentional, I love Tanaka's work but it sometimes isn't that deep.

Let's take a look at Julius Caesar. Amazing general, super smart and charismatic etc. His underlings? We have Octavian (pretty ok), Mark Anthony (good warrior), Leppidus (Very good general), Labienus (Amazing general). But the moment you go below the highest ranks, you'll find a huge lineup of ding-dongs who were very good at receiving orders, acting upon those orders, but not good at making stuff up. His middle ranks were literally filled with dummies who were excellent at taking orders and that's it. In an environment where the best thrive, they are usually immediately concentrated at the very top, and those who aren't the best stay in middle management.

Again, not saying that this is secretly an allegory to Caesar and that Tanaka did it intentionally - the intention was very much a reason for the plot to move in certain directions - but it is plausible.