The argument was made a few years back that this program was cpu intensive and not gpu intensive. Well i think that's starting to change now, Especially with the west coast map release. One of my GTX 650tis is now crying for mercy and can't even run with dynamic reflections enabled on this map. Id love to be able to use both my cards for this sim. Are the chances for that increasing at all?.
nVidia is planning on phasing out SLI support over the next years, and AMD has started calling Crossfire simply "MultiGPU" as if they're planning on phasing it out, too. This is due to complications with DirectX versions and how much effort is required on the game developer's part for it to even work. MultiGPU support isn't logical going into the future, for both card manufacturers and game developers. The amount of people running more than one graphics card is getting lower by the year. It wouldn't makes sense to support it given how hard these guys are working on updates, and to suddenly stop and go to work on MultiGPU support instead of content.
Tbh i dont think at least 2 way sli/Multi gpu is going anywhere for quite a while, not till a single card can handle 4k max everything with 60-100+fps, Not even counting the 5k and beginning of 8k resolution monitors on the market where 1 gpu simply wont be enough.
The drivers from card distributors aren't going anywhere for multiGPU support, but the support for it in games will be slowing down if not disappearing all together in the coming years.
Just as an FYI for AMD card users, if you have a crossfire setup, you can force it to run in BeamNG through Radeon settings here...