I'm in the same boat, only just reinstalled after quite a long hiatus. Main reasons are as Woz stated:
1) no new content (enter patch Y)
2) not enough racers online in my timezone
Point 2) also means I have next to no options on which server I join. It's extremely rare to get a server with the options I want, I always have to just race whatever cars the other 2 aussies are racing at the time
Either that or I join an EU server and lag everyone out. Actually most of the time I just create my own server and poke a mate to join me. Sometimes someone else will join. Sometimes.
Of course Point 2) is a direct result of Point 1! I can only PRAY that SCAVIER don't plan on tackling S3 all by themselves. Scawen said himself in a recent post that things are taking longer to develop now because basically the bar has been raised. They really need a larger team if they expect this sim to develop quick enough to stay popular.
I'll finish by saying thanks for Patch Y, I love the FBM. When S2 is finished it'll be a great achievement indeed.