I'm sure Howard both made and shot longbows because they worked best for him.
I've been fortunate enough to have met and had classes from some of the more successful and well known archery instructors teaching today. Back in my golf days, I had lessons from my share of well known teaching professionals. Most, but not all of them, are very adamant about their own particular methods, as different as they are from each other. As a CPA, I have met some very successful businessmen, and most of them have been very adamant about their methods too. It seems to be a common trait among successful people from many different disciplines that when they find a formula that works for them, they cling to it. And if they're very successful, it's hard to argue with that. I've wondered at times why they won't be more openminded about things, because they're not stupid and must know there are other ways that work, but I guess they look at life as having thousands of ways to fail, and they were fortunate enough to stumble across one way that works, and they're not about to let loose of that.
I suspect Howard had a little of that in his personality. Just my guess, of course.