Luke: Well, more wealth than you can imagine!
Han Solo: I don't know, I can imagine quite a bit.
I suppose nobody thought they could ever line up the circumstances necessary for the way "Changes" resolved, either. And they didn't, until it became a plot point for the author.
Sure, Dresden can be an unreliable witness, and he can't know everything, but there remain some things which - were they even remotely possible with anything below deity-level power - would have inescapable world-altering ramifications, even if he himself had not come up with them.
Maybe this will change. Maybe the Hermione Grangers of the Dresdenverse will come out of the woodwork and turn all of these "facts" on their ear. Maybe the Ponder Stibbonses will build a Rube Goldberg-esque steam-and-ant-powered supercomputer that turns the White Council into a league of well-informed surgical nuclear holocausts waiting to happen. "Maybe" covers a lot of things. And that is where our games take place.
Until it becomes "plot," we should be guided the setting and its (meta)physics to confirm that we're on the same page. Thaumaturgy can theoretically reproduce any effect, it is true. But there's a certain point at which a GM gets to decide: "32-shift head exploding spell? sure. Tear the Demon out of a White Court Vampire? not going to get any traction on that."
Edit: "not going to get any traction on that using Thaumaturgy, anyway. How about a field trip to the Fairy Courts?"