Interesting. I haven't studied the plan cache in detail, so I guessed the answer.
There's a typo and a math error in the paragraph about query size:
There is a limit on the size of the query, which is 65,536 * network packet size. The default network packet size if 4,096 bytes (resulting in a maximum query size of 256MB), but the network packet size can be adjusted to a maximum value of 32,767 bytes (for a maximum query size of 2048GB)
65,536 x 32,767 is approximately 2048 MB, or 2 GB, which (hopefully) is more than enough for any query. A 2 TB query would be truly frightening! :w00t: