So take this comparison
Diesel makes a comeback: Cruze vs. TDI vs. Prius - News and reviews - Boston.com
Now after 7 years when you finally break even with the Prius has is the resale of a 7 year old TDI compared to a 7 year old Prius? What if you decided to keep them and keep driving at that point what car needs expensive batteries and which is known to keep going 200-300k without drama? What if you did this same comparison with a 1.0 ecoboost Fiesta which is over $10,000 less then a Prius and gets even closer economy, I don't think you would ever recover the cost.