It's completely pointless to separate operating costs vs purchase cost. When you do the math (and many have), you don't (certainly I wouldn't) break even until you're outside the warranty period.
You're second argument I agree with, the ED is a want for the majority of ED buyers rather a cost savings choice. However, the hemi vs v6 is not on the same scale as ED vs Hemi. Some owners here have reported that the V6 has trouble maintaining highway speeds under wind or hilly conditions, towing even a small trailer just amplifies that. I owned the exact same v6 in my Jeep GC for 5 years, the poor drive train performance was pretty much the clincher for getting rid of it, the rest of the GC was absolutely awesome in every way.
The Hemi outperforms both the ED and the V6 in acceleration and towing. So; when comparing ED vs V6 vs V8, the obvious choice for max fun + max towing + max cost savings, that has to equal the Hemi for most people. The ED's only real benefit over the Hemi is fuel savings, but that won't kick in until warranty has expired and then you're on the hook for any EGR repairs ... and then you just lost all your savings. That's what we're saying, there is a _chance_ you can save money with the ED, but it's a slim one for most people. And "fun factor", well, the Hemi has more fun in my opinion (the sound track is stunning), but some may still prefer the driving style of a diesel.