Personally, I'd like us all to define what "that often is." To me, a rate of over 50% is "that often." Though I generally don't fire tank guns at M3s; I mostly gave up back in Aces High I due to this bug.
The "random chance" and "luck" argument (in terms of those actually arguing to keep it) is also moot if you listen to one of HiTech's mission statements, generally brought up when people discuss gun jams and engine failures; it can be paraphrased to there being no random failures, no chance happenings, and no difference between identical vehicles so as to give everyone the same chance. Now, it's true that everyone faces the same M3-bounce problem, but to put it up to "sheer luck" or ammunition failure is to oppose it to how the game has been stated to be.