Bio-enactive framework: The perpetual life or ultimate death of the cell in the myth

(Cummins, 2016, p.3)

Although I know it's largely figurative, I can’t seem to resist my existential or reductionist tenancies for seeking out something else in the milieu for the (excellently named) 'cell in the myth' described by Cummins and De Jesus (2016).

As I read the authors’ account of their bio-enactive framework I imagined the cell running out of glucose.  But, what in the milieu causes glucose to run out?  Will the cell die without glucose?  What exactly is present in the milieu or the organism that causes the cell to die?  Otherwise, if glucose doesn’t run out, does the cell live forever?  If glucose never runs out and the cell lives forever, why would the cell evolve movement at all?  Why don't cells just evolve to grow on/ close to glucose deposits instead?  If cells grew on glucose, and didn't need to move, would cells have evolved in the first place?