If they charge these big numbers more it's precisely because they're trying to capture some of the embarrassingly better value you get from vertical scaling. It's a testament to vertical scaling's effectiveness that they _can_ do so.
No, because you pay a fixed cost to get higher performance and then benefit through the whole lifetime of the product (I'm assuming you are purchasing rationally and keep your machines loaded at 75% or better, and your software is not egregiously wasteful).
