I'm starting to doubt not just the feasibility of quantum computers but their possibility. Let me give you an analogy. Let's say you have a wooden stick. You can use a stick to store information. If you think of the stick as being one unit long, you can place a tick mark anywhere on the stick, representing a real number. Real numbers have infinite precision, so you can store an infinite amount of information on a wooden stick. Of course, it's absurd for obvious reasons. I suspect the same will happen with quantum computing. While theoretically quantum computers are supposed to provide an exponential speedup for certain algorithms, actually implementing hardware to do that might require something equally as absurd as my stick example. Instead of an exponential speedup we might end up with something comparable to classical computers due to these limitations.