FWIW, I read Lincoln and the Tools of War a number of years ago and found that when I delved into researching some of the details in it I came to the following conclusions:
Bruce was pushing an idea and cherry-picked information that supported the premise that Lincoln had been far more instrumental in weapons development than was actually the case. In some of those instances, he favored second-hand accounts written years later over first-hand accounts written at the time.
Bruce tended to demonize people to make Lincoln look like he was overcoming idiotic bureaucratic obstacles. The Ordnance Department was certainly conservative, but oftentimes that was the result of previous experiences that proved to be sound reasoning. They weren't exactly perfect in hindsight, but Bruce's account often lacks relevant context.
Bruce had no understanding of manufacturing or engineering and consequently didn't really understand the subject he was writing about. I say this as a former mechanical engineer, Bruce's lack of understanding leads him to sweeping conclusions that fail to comprehend the difficulties and risks of doing what he thought should have been done.
JMHO, but those are my thoughts on that particular book. I'm pretty sure the book actually won a prize of some kind, so obviously others felt differently. I have to admit I really hate that book, it has had a long-lasting influence due to other authors taking it at face value and repeating some of the more dubious conclusions.