This is really clever & I like it, but the fatal flaws in it are 1) the "tasks of a human job" circle changes shape over time just like the "tasks AI can do" shape changes over time, & 2) "doing tasks" is just one proxy for "intelligence".
Defining "intelligence" as "the ability to do tasks a human can do" is the drunk looking for his keys under the lamp post because that's where the light is. I don't actually object to this as a starting place -- we have to start somewhere -- but it's not an ending place.