How many times can i charge iPad2 Battery?
Apple has a great page on batteries and it does say that they are designed to still have 80% of their capacity remaining after 1000 charge cycles.

Not all batteries are perfect, so you could have problems even on the second charge. Heat, always having it charged and deep discharge can also cause them to fail or wear out before you get to 1000 charges.

Don't confuse an isolated failure or anecdotal evidence for the overall statistics for a million devices seen as a group. Also, damage like wetness or other failures of the electronics can bring down a perfect battery so it's hard to know what might cause a specific failure without taking it apart.