Can AI be considered alive? If not, what’s missing?

Life is usually defined by self-replication, adaptation, and autonomous decision-making.

AI can already self-improve, rewrite its own code, and make independent decisions within its programming constraints. Some argue that AI could become a new form of non-biological life. But if it’s not alive, what is missing?
If life is just a set of biological processes, then AI will never be alive. But if life is defined by intelligence, adaptation, and autonomy, then is there a threshold where AI suddenly counts as a living entity?

Is "life" just a human-centered definition that we will be forced to rewrite in the future?