@CardTheEngineer, I am a long time linux user and although I would salute the initiative and personally enjoy a linux native version of SketchUp, I’m not sure about the assumptions made in this post 
TLDR version:
If it’s that easy and there’s such a market for it, I trust Trimble to make it happen. My personal opinion/feeling: it won’t because it would require a big developement effort from the (capable, yes but small) dev team and the market might not be that great for it.
MARKET SHARE / FINANCIAL INCENTIVE
In 2012, at the moment Trimble bought SketchUp from Google, this article reported a base of 2 million active users of SketchUp with somewhere between one third to one half of them running the Pro version. Let’s be super generous and say it was the solid half (1 million) and that it has grown 5x since (Woah! that’s growth!).
Forgetting mobile OSes from the reported 3.3 billion internet users and breaking it down into only three OS category to do the math is also probably wrong but let’s say it’s right:
So out of 3 billion of Windows users + 230 millions of Mac OS users, 10 million (0.3%) are active, ongoing SketchUp Make users and 5 million (0.15%) are SketchUp Pro users.
I don’t believe it’s fair to say 1 in 10 (10%) of linux users will become SketchUp users, let alone paying users.
Applying the very generous ratios above, the market for Pro license on Linux would be 80190 users. The temptation is strong to assume that all those licenses would be new users (@ 700$US a pop) but it would also be wrong as I’m sure some of them would be actual Windows SU users simply activating their Pro license (on 100$US yearly maintenance) on Linux instead of Windows.
Even with a Craftman license (half the price of the Pro license), as suggested in this post, I’m not sure we would ever come close to 10%.
The Maker movement is great but without Pro licences sales, there is no such thing as a market. At the end of the day it is the Pro licenses that brings water to the mill…
BSD != LINUX
Although I am no developer myself, thinking that since a Mac OS (based on BSD) version exist, a Linux version “shouldn’t be too hard to achieve” is probably underestimating the developement work it would involve to get to a stable, solid linux version that is not a customer service’s nightmare to support. Even if they share OpenGL for viewport operations, I am under the impression that low-level code cannot just simply be reused without substantial adaptation/modifications.
ANDROID != LINUX
Android make use of the linux kernel indeed but once again, it is my understanding that it’s a completely different animal and developement for one differs substantially from the other. There is a 10$ SketchUp Viewer for Android already. Are we going to see an Android port of SketchUp before a Linux Desktop one? Who knows. Personally, I’m not sure I’d use it. Would extensions just work? Hum I doubt it. Would there be any rendering plugins? Distributed V-Ray rendering on your tablet and phone, anyone? I can already feel the heat in my pocket!
CONCLUSION
SketchUp is not the only software on my Windows partition. Dual-booting with a SSD in a matter of seconds nowadays so it’s not so annoying to go back and forth anymore.
Would it be nice to have SketchUp on Linux? Sure. I’ll be first in line. Is there a severe need for it? I don’t know if I’d say that.
As much as I’d love to see SketchUp on Linux, I will be pleasantly surprised if it ever happens.
And if it does happens, I do hope the Linux community supports it financially and do hope this time I won’t hear the usual stream of complaints over the choice of distro (Debian vs RedHat vs Suse vs …), toolkit (GTK vs QT vs TclTK vs…), dependencies (who uses XYZlib anymore?!) or [insert your favorite polarized debate here]… 