And my experience is hardly singular -- according to the poll, a full 55% of respondents have not yet opened up their Cracked Eggs to find the mount. 4% found it on their first try (bastards -- that number seems incredibly high), and almost 14% went for the joke "Oracles?" answer, or maybe just have no idea what the question is about. Obviously this is hardly a scientific poll, so we can't calculate drop rates or anything like that (most database sites put the drop at around 2%, which means on average 50 eggs to a drake, or almost a year of farming), but it's pretty clear that the Proto-drake is a supremely rare commodity.
And that's not surprising either -- other than the Time-Lost Proto-drake, this is pretty much the easiest Proto to get, especially since the achievement drakes have left the building. Blizzard probably likes this Proto-drake just as rare as it is. As for me, I'll keep buying every week on the dot -- it's got to be in that egg sometime, right?