Yup, some people plateau for quite a while, but then can decline precipitously.
And Anvil's point is well-taken. This is not a disease of spontaneous remission or improvement. In my case, when I quit, I was still able to "control" the drinking to some extent--if I had to. But I could only do it for periods of time, and the physical and mental addiction were progressing in the meantime. So someone looking at me might not really know how bad it had gotten, though they might think I smelled of alcohol or was not mentally "with it" much of the time.