Absolutely, I agree that when it comes to rendering, RAM speed will matter much, much more, since everything is essentially happening within the RAM. Calculations are calculated off the RAM and returned to the RAM. And the longer the render, the more it will matter. Speaking generally, and for general PC use, then the SSD will produce much more realized and noticeable results for general PC use. Since I have never had a render deadline, I have never sat at my PC and thought "I really could use some faster RAM", nor have I ever considered RAM speed when upgrading it (in fact, I feel lucky when I can track down something that's actually compatible).
I do not doubt that faster RAM speed will produce better and measurable results for rendering. Personally speaking, of course, whether a render takes 90 minutes or 65 minutes won't affect my workflow at all.