Why is Git not considered a "block chain"?

Git's internal data structure is a tree of data objects, wherein each objects only points to its predecessor. Each data block is hashed. Modifying (bit error or attack) an intermediate block will be noticed when the saved hash and the actual hash deviate. How is this concept different from block chain? Git is not listed as an example of block chains, but at least in summaries, both data structure

[progrhyme]

"なぜGitは「ブロックチェーン」と見なされないのですか？"