I think the reason why they are getting expensive is the fact that they CAN !
There is nothing out there that is even remotely similar. The patents for their units have long run out ! But no one is interested in doing the research and development, designing, and manufacturing of these things because of this piddly market!
Honestly now , how many new tracks are going to buy this unit ???
50 a year ? Yeah ....... It's simply not worth it !!!!! Suck it up and spring for the unit or whine about it !!! Unless your independantly wealthy and can afford to develop a new unit, give it a rest.
If you could come up with a transponder that recorded as you passed over or under a trigger device, and then dumped this info to the main computer as it passed the main loop each lap..... that would be WAY cool , even better yet it constantly sent info to the race computer about sector times,and such this would be the $hits!!!
Yeah yeah I know "keep dreaming Alice, someday you will get to Wonderland"