I considered it, but dynamism refers to personality and philosophy, while dynamicity is just the condition of being dynamic.

The Wikipedia disambiguation for Dynamism (last edited in March) includes:

"Dynamism (computing), When any process in computer is using Dynamic management methods for its processing/computing/memory management/parallelism handling for being able to give more user friendly work that are more easy to interact and modify."

... for whatever that's worth.

Consider:

  staticity
  staticness
  statism

That doesn't work because statism comes from "state", not "static" - I don't think there's a comparable derivation for "dynamism".