I'm going to go against what the others are saying and think that it's possible some other technology might come to replace it. Blockchain is a technology, and technology is advancing fast. Old school televisions have been replaced with flat screen TVs, then it was upgraded to Smart TVs and now there's even curved TVs. All same "technology" but just have been upgraded and evolved from its predecessors. It will be the same with blockchain. We don't know why and how it will "fail" but if and when it does, some other technology will emerge to take its place.