I would dearly love to have proper Linux support for my Fireface UCX. I currently use Windows but would love to switch to Linux and I am constantly evaluating if I can jump yet. Drivers for my RME interface are a major component in that decision.
RME says the main problem is lack of available developer resources to commit to development for Linux, as a Software Engineer working in a large company I completely understand and sympathize with this problem. I also understand that developing Linux support is not a one time thing, there is also the on-going overhead of maintenance and support so that it continues to work as Linux OSes are updated, and also the fact that every new feature for Win/Mac must also be added to the Linux version.
Going from 2 to 3 supported OSes adds something like 50% to the cost of all software development for RME for the rest of forever, and that's AFTER they've done the initial up-front project of releasing Linux support V1.0. However, nothing is impossible, so let's consider what would have to happen for RME to switch from a "No" to a "Yes".
In business, time and money are often interchangeable, indeed where I work (a Fortune 500 tech company) everyone just uses the term "resources" to refer to the time/money duality in relation to projects. RME's reluctance support Linux is likely because their current business model (which never factored in the cost for Linux support for current products), and probably also the market ROI on future sales, does not provide enough resources to afford a Linux version of the various RME drivers and software.
There are two ways I can see that RME could get more resources for this project. One is crowd funding, and the other is open source development.
The initial project could be partially funded by a crowd fund campaign. I say "partially" because my finger-in-the-air guess at the cost of delivering drivers and TotalMix 1.0 for Linux would be a million dollars at the bare minimum and probably a lot more, and that's assuming that much of it can be "ported" rather than re-written. A crowd fund campaign appealing to "RME users who want to pay for Linux support" wouldn't get anywhere near that kind of money. But hey, any amount of resources is resources, this could at least partially fill the gap.
Another possibility is open source which addresses the other side of the time/money equation. If the Linux version was some form of open or "mixed" source, then RME could reduce it's own spend by leveraging free labor from the open source community. There are a lot of complications here though, not just regarding intellectual property, but also RME's control over their "brand".
Like it or not, most people will still perceive that open-source project as "RME's responsibility" and if the project does not quickly develop a strong community of quality contributors then RME will be left holding the baby on a half-baked project that makes them look bad and, what's worse, they don't have the resources to fix. However, where there is risk, there is also potential for reward, a successful community-resourced project would significantly boost RME's brand in many ways, even beyond just the Linux users who are using the software. Most users of RME products would be highly technical people who are tinkerers at heart, and all tinkerers appreciate open systems.
As I write this out and think about it, it occurs to me that another route that protects RME from potential fallout would be an independant open source project that was not directly associated with RME, but has their blessing and support, particularly in the technical specifics required to get the drivers running, perhaps via an initial contribution of code. If the project doesn't take off, well it's not an RME project and RME never officially announced Linux support, but if it does, then RME gets all the benefits of having Linux support for their products with little risk.
Anywho, that's my 2c on it...