Xbox 360 Running out of dragons to battle

I've been under the impression that dragons in general just keep respawning given enough time. Which is great when trying to elevate my fighting skill levels this time around through the game; I would customarily do what I call the 'Grand Tour', fast travel in consecutive sequence to each of the dragon shrines or temples or whatever they're officially called (including Arcwind Point, at least I think that's what it's called), bump off the resident lizard (usually an Ancient), then move on to the next one. After clearing each out I'd go and goof off at a few non-dragon sites for a while, then do the 'Grand Tour' all over again.

The first sign that something was going sideways was with the ancillary stuff next to each shrine/word wall. Treasure chests weren't respawning. Nearby Snowberry bushes and other plants weren't respawning. Dead adventurers that the dragon previously killed remained 'empty'. Then several of the shrines stopped respawning dragons altogether. So far Eldersblood Peak, Skyborn Altar and Shearpoint have shut down and apparently become dragon-free zones. Mount Anthor looks to be next with Bonestrewn Crest also showing signs of the same issue with how long it takes a dragon to respawn.

As for the freelance dragons--the ones who pop up around Skyrim when I'm out roaming about--those do pop up from time to time, but even those seem to be much rarer than when I played through Skyrim my first couple of times. Those dragons NEVER showed up when I was doing my 'Grand Tour' loops, either during or between loops; they only started popping up as I've dramatically increased the time between loops trying to get the now dead dragon shrines to start respawning new lizards.

Anyone else play Skyrim this way and encounter anything similar? Out of curiosity I'm now considering the notion of trying to break the remaining shrines. Wholly monotonous, definitely, but the idea of actually being virtually dragon-free is worth an attempt (I suppose I'll have to off my BFF Paarthunax but hey, it's a noble experiment and for a good cause...)

Have the dead dragons disappeared or are they still there? Sometimes I've had them stick around dead, but whole and still twitching which could fool the game into not reap awning because it never fully died

Yeah, there seems to be an issue where dragons stop spawning at those locations. Had it happen on PS3 and could never find a solution (got results for a different problem). Try waiting in-game for a month or something to that nature.