the rate of fire race might be over, but there is still plenty of development that can be done to bring up effeciency, reduce weight, improve ergonomics, programming, consistancy, lower kick, etc.
why a new model every year? allows people to spend their readies on the latest gat and put money into the manufacturers pocket so they can get on with all that development.
granted, it doesn't need to be yearly, but it does need to happen regularly enough to keep the interest up in the markers and keep the company going.
unless you're "on the bandwagon" then there is no need to out and grab the latest from however, when the next offering from someone else is a handful of weeks away.
if eclipse having something really major developmentally coming up, then after seeing dye's release there'll be no great shakes in them having a later release date. the DM9 doesn't come across as different enough (on paper - having not shot one i would reserve my judgement) to the DM8 to pull the Eclipse brigade away from their items of fixation.