re: Even if it did not explode...
Lets suppose that you got that "donut" when you were a child and it was filled to a certain pressure at that time, now suppose that it does not leak, and then suppose that no one adds or takes any air out of it.
Now suppose that the atmospheric pressure was decreasing very slowly.
Do you think that your grand children would notice that the donut is harder, larger, and different in shape, when they became adults?
What I am saying is that it is easy to ignore slight changes when they happen over long periods of time.
I would like to see a mercury barometer somewhere close to sea level, simply to confirm that the old measurements still hold true.