Eucon is - afaik - the only other Ethernet based control protocol outside of Avid's own protocol. They bought Euphonix but the protocol was already in wide use.
Not sure what Eucon has to do with being "suckered into buying PT". ?? Any PT user with such a control surface can move to any other workstation that supports Eucon, which is the rest of the so called majors?
So a PT user who got tired of it could move to Cubendo, Logic, Sonar, Samplitude, DP. Pyramix, etc and take their Eucon control surface with them.
How exactly is that being "locked into Avid's hardware"? Did the OP ask to support the Avid D-Command? I have no clue what some people here are talking about.
Here is the list of software that support Eucon...
http://avid.force.com/pkb/articles/e...n&DocType=1083