I yoosta preach to people (especially at work) about the advantages of commuting in an ecomobile vs. the typical V8 4x4. It was quite easy to math out a good estimate of the savings, which proved that getting the ecocar was well worth it
in spite of it being an additional vehicle instead of a guzzler replacement,
especially if it was an inexpensive beater. IIRC Oftentimes the payback period was well under one year and then after that the savings were all gravy. Sadly I can't think of one example of someone who saw the light after seeing the math.
I guess protecting that ego projection device A.K.A. the big guzzlers was a worthwhile expenditure.