Have you guys ever considered that almost the entire visual effects industry (at studio level) uses Linux as default operative system?
I have been in this industry for many years and I can tell you that the lack of Photoshop for Linux has always been a problem in any visual effect studio since a 2D image manipulation software is required at almost every stage of any VFX pipeline. I have heard of many workarounds, such as using GIMP, or run Photoshop with Wine, or even having a separate Windows machine sitting next most Linux workstations just to allow the artists to use Photoshop when needed.
I think here you have a big opportunity to fill an industry need where the competition hasn't arrived yet. If you made Affinity Photo for Linux, you would most likely sell thousands of seats immediately to EVERY major visual effects studio in the world. That alone should be enough to recoup your porting investment. I agree that the rest of the sales (the mainstream Linux community) would probably be marginal, yet your investment has already been repaid for.
