I've seen them go opposite as well, up in the line-up.

My bike is a 2014 Giant Escape 1. I bought it in early March, thus he had nothing in his shop for 2014 yet. I chose Giant because he is really the only shop around, the Escape because I researched and knew I wanted a hybrid, and the Escape 1 tier because I wanted a carbon fork and 9 speed cassette.

He had a slew of 2013's sitting in his shop. When I looked at the leftover 2013's, the Escape 1 had aluminum forks, an 8 speed cassette and SRAM shifters which I didn't like how both triggers were actuated with the thumb. So, the specs got better for the same tier between those years.

The car analogy doesn't really work too well. Automobiles are generally updated in generations. There may be slight differences year to year, but as for the majority of the car, it will be the same. My car for example is a Mark IV (generation 4) VW Jetta, particularly a 2003. The MK4 VW line started in 2001 and was basically the same through 2005. There was a computer program change on the 1.8 turbo engine that bumped it from 150 to 180 hp and that is really the only difference. Stuff like that happens, but it is still the same engine (as well as the same engine used up until the 2.0 turbo came in 2009 I think.)