Mode S at MACC was relatively easy to achieve from technical perspective as the same RDP system already in place and Mode S already used by LTC, as it will be for Prestwick. Unfortunately, the LAC RDP system is different, and not easily upgradeable. However, work is in the pipeline to bring it in sometime soon. CAA DAP already had the request to extend the Mode S airpace outside of the LTMA.
The best things come to those who wait, LAC just has to wait a bit longer!
Don't forget, LAC is served by 7 Mode S radars already, so benefit is already being given, even if you can't get to the DAPS, etc.