Have killed lots of turkey early but most have been later in the morning or throughout the afternoon. If I do not get a response early I will settle in somewhere I know turkeys like to be or if on a unfamiliar place for a while and take some good naps calling some when I wake up enough. More than once have been woken up by a gobbler in range looking for that hen that was talking there earlier. Somewhere around 10 I will start hunting in earnest again having given the gobblers time to get tired of chasing those no longer receptive hens that they have been with since before daylight and are looking for more hens. Those later in the morning can be some of the easiest to call in. Run and gun is fun also but I do not run nearly as well as I once did.
One of the videos I posted was of my nephew's first bird. The day before we had a gobbler lock up behind a barbed wire fence at the 50 yard mark. He simply would not cross that barrier. The next day was the last day of the season. We set up early and the gobblers left the roost and headed out into a field 400 yards away and they wouldn't even gobble at the sound of the call. We moved spot and called for an hour. We moved again, called and thought we heard a gobble from a long way off, across the county road with barbed wire fences on both sides. That bird called again but we could tell it was closer.
45 minutes later he was standing in the middle of a very busy oilfield gravel road, fanned out and gobbling. He still had 75 more yards to close for a shot. He eventually just appeared through the brush. My nephew was able to pile him up. That was a lot more fun than shooting him myself.
That hunt falls right in line with what you stated. I couldn't believe we got one from so far that late in the morning. I had never hunted so late and only did it because I didn't want to give up on getting my nephew a bird.