Some responses to various assertions in your post: - transistor density: only when taking 2D density into account. There is a whole third dimension to start us

Some responses to various assertions in your post: - transistor density: only when taking 2D density into account. There is a whole third dimension to start using. Although it won't scale exponentially in sheer numbers, it may scale by introducting new topologies. - 'Heisenberg effect': single atom transistors have been built and uncertainty in the observation of its state is not the problem. The Heisenberg uncertainty principle is not the issue here. - Quantum computing will not solve the issue. It can solve some specific classes of problems spectacularly fast. For most common problems, it's not even (significantly) faster in theory. - Nobody knows what kind of quantum computers will be technologically possible. There is no reason whatsoever to assume that quantum computing will ever replace 'regular' computing. My personal prediction is that it will track the record of fusion power for the decades to come: i.e. no practically useful results. Experiments in my university tended to go awry if someone in across the hall received a mobile telephone call. They invested quite some time and energy into shielding the experiments, to little avail. And a minor nitpick: - "quantum physics" is a theory. The obstacle isn't "quantum physics", it's the experimentally observed granularity of reality and what you can reasonably build out of those granules. "Quantum physics" is the problem as much in this realm as "Quantum physics" is the reason you can't make anything you want out of legos.