Upper band propagation for me is just so scant that I don't even tune to 10 or 12 meters anymore; I think my limit is 15 meters to derive any half way decent contacts. In my opinion, I wasn't missing anything even when 10 meters was open a few years ago. Throw in a disappointing sunspot cycle and now on the decline and all that 10 meters appears to offer Hams are hope and a prayer. All the ARRL promises were just hype concerning upper band propagation a few years ago. And then poof, it became apparent that the propagation was going to be disappointing. Too bad we can't trade in all that useless spectrum on 12, 10, and 6 meters for expanded spectrum on the lower bands. And while we're at it throw back the lower 100 Khz portion of 160 meters for more space in the 40 meter band. Yeah, I know that this is just wishful fantasy thinking on my part but I don't have the patience to catch some odd fifteen minutes of an unusually great opening on 10 meters and listen to empty noise the rest of the time.
I don't know how long you've been a ham radio operator, but I have worked the world and all 50 states from here in Kentucky on 10 meters with nothing more than a C.B. antenna or dipole and 25 Watts. Yeah, the current sunspot cycle was a dud, and we have to wait a few years for the next one. This hobby, much like many other hobbies, often involves patience, knowledge, and luck. I certainly wouldn't trade any of that "useless" spectrum on 12, 10, or 6 Meters like you propose. Hams used to have privileges on the 11 meter band, and we lost it, primarily because of what you are suggesting on this post. 10 meters and some of the the other higher-frequency bands are open to somewhere a lot more often than you would think. If no one ever bothers to put out a "CQ" how do you expect to make any contacts?

That is like going fishing without baiting your hook and then throwing it in the water. I can't tell you the number of times I have tuned across a supposedly "dead" 10 meter band, only to call "CQ" for a few minutes and have someone thousands of miles away come back to me. Patience and a good antenna go a long way sometimes, especially when the solar activity is in decline like it is right now. I still wouldn't take your suggestion even under the worst of conditions.
KU4UV