Habitat management can only achieve so much. I spent 14 years and over 100k learning that all the experts were helpful to some degree but mostly guessing. You change one thing and something unexpected was certain to come, with what you hoped would happen, if you were lucky. Mother Nature would do what it wanted to and man can not exceed that level for long and worse they can easily screw it up with almost no effort.
In the end the state game management introduced wild turkeys on my land without telling me. That was the final straw. In two years I went from 15-18 viable coveys to one. I did not even associate the rapid die off of quail to the infestation of turkeys until the saw it repeated two years later on another farm I own. I had three coveys every year and sometimes five or six. Two years after the state introduced turkeys on the farm across the road I had multiple turkeys in three sections of woods and zero quail. The state biologist assured me that turkeys and quail easily coexisted. BS in my experience.
I'd love to see long term increases in game population but have concluded that it's in Gods hands not mans.