AB,
If such miracles were the norm, they would not be seen as miracles by secularists, but naturally occurring phenomena. Just as the miracle of human free will has been dismissed as "natural" since the secularist thinking assumes that it can't be true free will, but a naturally induced reaction over which there can be no control.
So just for funsies, imagine for a moment that there is no "God", and that prayers don't therefore get answered. Imagine too that, despite this, still some people believe that both these conjectures were true.
What then would happen when those people prayed for a desired outcome? The answer would be just as you described - almost always the hope wouldn't be realised, but every now and and again it would because surprising things happen quite often for entirely naturalistic reasons.
What then would you make of such people when it was explained to them that the world behaves just as you'd expect it to if there was no "God", and in reply they indulged in fantastically convoluted casuistry along the lines of, "But maybe God has to ration his favours capriciously so that those few people at least would somehow think the "answered prayer" hypothesis to be more credible that way"?
Does it really not occur to you that the
opposite of that is more sensible - if this God of your answered prayers
more frequently than you'd expect surprising thing to happen anyway,
then there'd be something to think about?
You might want to try looking up "Occam's razor" about now too by the way.