Thw 12 hour limit has nothing to do with people canceling. The numbers were being lost long before the 12 hour limit was instituted.
Basically the 12 hour limit is being opposed by the many who dont like being punished by the actions of the few. The cheaters! It was very common to see players leave channel, or change countries, after a mission was posted and like clock work you'd see the same few guys in their 4 Hispano Typhie right on schedule, in the middle of nowhere, a quiet sector, to intercept a mission they had dishonestly changed countries to intercept. I actually stopped flying missions and even left the game in disgust.
However......
I believe it sad the many were punished due to the very few. Perhaps if the many would have acknowledged the obvious more vocally it could have been averted. But players, most of all the honest ones, put blinders on when these accusations happen and refuse to see the big picture. I myself dont agree with the 12 hour rule cause its to stringent but I understand the reasoning behind it.
The game lost players cause it failed to evolve and improve its graphics. The maps grew stale and now the big maps, most of all during off times, are driving even more players away. It has survived on the strength of its flight model and loyalty of a core group of older guys. By current standards the game just doesnt look good, certainly not $180 a year good. Thats why. The 12 hour rule has nothing to do with it.