Late morning can be very effective. Go to where you the birds are and do more sitting and soft calling instead of trying to cover a lot of ground and calling aggressively.

Best time to hunt is after 10: if you can locate a turkey still gobbling late, get some good cover between you and him and walk right to it. Set up and call him right in. If Nothing's gobbling, set up in a likely spot and call. They may come in silent so keep watching.

I don't think I've ever killed a bird before 10am.
My problem is land, I prefer private land but am limited to small tracts, 100 acre farms. The landowners (and admittedly myself) ride dirt bikes and quads around in the evenings so its impossible to put one to bed, so I never get them on the roost. Just set-up and call and I've been pretty successful mid-day, even hunting on the track we ride on daily.

I think it CAN be easier to kill a bird mid-morning, but you have to do several things right to make it happen.

First, you need a willing participant. I don't think birds gobble nearly as readily later in the morning, at least, they don't where I hunt. Part of that has to do with noise... trucks, cars, logging, trains, planes, wind, whatever... they will gobble at any dang thing in the tree... but not so much later in the morning.... nor near as frequenlty. There are, and have been in my experience, plenty of exceptions though.... this is just a general comparison.

I have found that scouting is KEY to success in the afternoon (course its key to success period), but what I mean here is that if you know a birds travel path and more or less at what time he is where... then you can do a lot with your two hour time window. They can see better once the sun is up good also, so you need to try and pin-point about where one is at when he sounds off, and also try and figure out if he is holding ground or heading to you already... never good to meet one on foot in the middle.

A few years ago, there a survey in Turkey Call (now Turkey Country) magazine on when gobblers were shot. The most commonly reported time for killing a tom, as I recall, was around 9:30am.

Hunt when you can. I busted a bird at 3:15pm one afternoon about 7 yrs ago.