Occam's razor is a guideline, not an immutable law.

Occam's razor would immediately discard quantum theory. Does that make it false?

Forgive my ignorance but haven't there been experiments that prove quantum theory? Why all the fuss about quantum computers if its just a pie in the sky hypothesis? (It's not a field I am familiar with other than on a very superficial level, so an "explain it like I'm 5" would be most useful in responses to my points).

> Occam's razor would immediately discard quantum theory

No, it to wouldn't; quantum theory is quite plausibly the most parsimonious explanation consistent with the evidence.

The point is that it would seem ridiculous to start from nothing and jump to such a counter-intuitive theory.

Occam's Razor has nothing to do with starting from nothing, it has to do with selecting among competing explanations for a set of known facts.