No, the 2012 Doomsday scenario was not a scam, but a misunderstanding and superstition. The Mayan calendar did not actually end on December 22, 2012, but began a new cycle. On top of this, the populace at large tends to be superstitious about anything written by an ancient people that may affect us today.
The whole doomsday of 2012 should not be considered a scam as nobody was really made to spend or lose money. I think it was an urban legend exaggerated by paranoid people who live to cause a panic in their own lives as well as work everyone else up into a frenzy.