This is kind of true, but not quite right. If there's a flaw serious enough to be too hard to patch, it's likely that some problem would have come up later. T

This is kind of true, but not quite right. If there's a flaw serious enough to be too hard to patch, it's likely that some problem would have come up later. That is, some serious contradiction would be reached, or something really weird would happen that yells "either this is really unexpected, or you have a problem earlier." To stretch analogies: It seems like you're analogy is saying: My card pyramid is built, but now if I remove a card, it all falls down. The more apt analogy is: When you're building a structure, you might be off a little the first time you build it, but if the overarching design is sound it will still work out and you can fix it and try to be perfect again. If the overarching design is not sound, you won't be able to build it at all. What I'm trying to say is, problems in the more bottom layers are very unlikely.