I would agree that buying a $3000 camera to shoot in crop mod is a bit of stretch unless you had a large collection of high end DX lenses you could not sell.
I have 3 Dx lenses: the basic Nikon kit 18-70 (which is good lens for very little money), a Tokina 12-24 which is a good but not incredible lens. I can live without/easily replace these two. In fact, my 20mm 2.8 adequately replaces the 12-24. What I would really miss and have to spend a ton of money to replace is my Sigma 50-150 2.8. This is a superb, compact lens with an ideal focal range. I'd need a more expensive and much heavier/bulkier 70-200 to replace it and it still wouldn't cover the comparable focal range.