You're absolutely correct in a "money no object" analysis. However, what I'm trying to accomplish is the best reasonable set of Ls ( I don't believe I'm calling L glass "reasonable") that I can afford and still carry around.
The 18-55 IS will cover the wide end for me as a non-L. The 38-360mm eq. L coverage of the two lenses will do 80% of what I need. I recently got a suggestion to take a 24-70 f2.8 instead of the 24-105 and that would fit in with your thoughts. Lastly, for a special event I can always rent a longer L, even a long prime.
I also still have my S5 which I still love and carry in the bag at all times. For a quick trip out to 432mm F3.5, it still works really well.