Me neither. 1000 cycles is an approximation, and it's usually within a wide range, just like a typical lithium-ion battery will last somewhere between 300-500 full charge cycles. Apple would only replace a laptop's battery if it was obviously defective, say it only held 1 hour charge after just 6 months of ownership. People have reported here that even after 12-16 months of usage, Apple wouldn't replace the battery for them.
The life of the 17" MBP's battery is probably estimated within a acceptable range, and it's rarely related to the age of the battery unless you're talking about exceptionally young batteries dying. These batteries will probably only last 3.5 years if used excessively (i.e. always on battery power), while it may last 6 years if it's treated well and not used excessively, or infrequently.
Like brakes in a car, its lifetime is too dependent on how you use it for them to cover it under warranty unless the case is exceptional.