I think that what Terry understands is the fact that there are a lot of racers out there that have 3 or even 4 personals already. Most of us have a a couple of transponders because we race a couple of classes.
So, pretty much all of the racers out there have spent $200 to $400+ on personals already. With the cost of racing (and gas to get there) try telling a racer that he needs to ditch the old transponders and see what they say. Personally I want no part of buying new transponders that may or may not work at a big race or national.
I think that any new system will need the following 3 things to be accepted.
1) Inexpensive decoder box - inexpensive meaning less than half the cost of AMB. Existing clubs and shops don't need another huge investment if they want to switch
2) The new system must be able to read existing AMB transponders so that people don't have to shell out even more cash. House transponders would still work eliminating that expense for existing tracks that want to switch.
3) The new transponders don't need to be compatable with AMB but the numbers can't conflict (perhaps adding the letters MRT at the end for instance)