Switchgrass in large CRP fields and wildlife habitat...

Not having seen a lot of tall grass prairie up close in my lifetime, I was overwhelmed the other day by some large CRP fields of head high switchgrass in N. TX. I had seen the large bunches scattered about in gulleys and crevasses before, but I was not familiar with it in such a large and thick environment. It was beautiful, and I'm sure it did a wonderful job as erosion control. But I question whether it was effective as wildlife habitat when sown so thickly without much plant diversity to compliment it as habitat.
Switchgrass is, indeed, an excellent forage for wildlife and especially noted for game bird seed forage and cover. But it has a very thick carpet underneath, much like other erosion control plants, and would be hard to navigate by young quail and turkeys... IMO. And without plant diversity and bare ground in between the bunches of switchgrass, I would think it's benefit as wildlife habitat would be limited.
That thinking was initiated when I asked about quail on the property and was told that you would never hear a quail calling on this property. It started me asking myself: Why? Not being personally familiar with the switchgrass prairies (only heresay), it just didn't make a lot of sense to me, at first. But after thinking it over, the lack of diversity in the fields has to be the reason.
But then, I am convinced that biology is an evolving science, and I never professed to have all the answers. But this issue deserves considerable study on my part. Maybe some of you have some helpful information or experience on the subject. If so, your input would be greatly appreciated.