1) Yes that is true, normal supercomputers can become more efficient and dangerous at some point. But I`m just telling that everyone is scaremongering about the quantum computers which are a so remote idea that a meteor hitting earth might be a bigger concern.

2) And then cant scale it up, because the entropy of the universe is too big for building it further. Qubits can only form in vacuum and at 0 degrees kelvin. The best they came up with was near 0 degree and they can only put together a few qubits because any tiny energy interference just collapses the entire buildup like a house of cards. You can't isolate the setup 100% from outside interference, it's impossible. Tons of neutrinos are bombarding the earth every milisecond, they pass through solid matter and emit radiation, not to mention the background radiation that has so big wavelength that can pass through anything. You build a qubit setup and a piece if particle just teleports right inside the setup emitting energy and the entire qubit system collapses. Quantum mechanics is a very complex science and I have read a lot upon it, and from what I can tell those that say that a functional quantum computer is possible, are either scaremongers or they are scammers trying to fool people.

3) Well yes, but after many many threads discussing it, and articles coming up on reddit about it all the time, at some point it looks like FUD. I believe there are bigger priorities than this.