Have you tried it? For the case you haven't then it would be really worth to give it a try.
It's true that Wine is not that what we expect as a native version. But within one year, I've seen incredible improvements from almost "unusable and buggy" to "like on windows" at least for everyday use.
I would muchly like if Google would show at least a little more interest and courtesy to solve the remaining flaws when using SU in Wine. Especially as the new version was an enduring regression (and I DID warn that this would happen).
As to "sketchup could grab a whole chunck of this market". That alone doesn't awaken interest by Google. You have to consider that SketchUp's development is financed by the Pro license fees. But you are very right in saying that money saved from Microsoft license fees can be spent on other software. Neither does linux have a less insignificant market share then the overhyped iPhone nor are linux users less willing to pay for quality apps (see the second reference).
I'm not official Google Support, just an ordinary forum member, and we'll have to find ways to use it. If you have any issues, I'll try my best to help you.