I have quite a good rig and run Il-2 and P3D at near maxed out settings and can't get (yet) DCS 2.5 to run - my guess (and that is all that it is) is that it is not a question of RAM or SSD but that DCS is still very much being tweaked and that in time it will run acceptably in most PC, it make take a couple of years to get there.

This is not unheard of - until P3D v2 I got used to very low FPS in FSX, took almost ten years for it to reach its full potential.