Most scientists and most doctors think thermodynamically – they think about equilibria, concentrations, and the like.
The body rarely has any process at equilibrium. Body dynamics are the resultant of competing rates: the rate of one set of processes versus the rate of competing processes. That is what is important to function and to health.
For example: why would those rare cancer cells that are rapidly growing, even if they can do oxidative phosphorylation (that is, their mitochondrial respiration is not impaired), still do glycolysis? It makes no thermodynamic sense – no, it does not. But it makes perfect kinetic sense, and in the human body KINETICS RULES!
Glycolysis produces a net of 2 ATP per glucose molecules and 2 exportable lactic acid molecules (which the liver, kidneys, and gut turn back into sugar).
Glycolysis, Krebs cycle, and Oxidative phosphorylation typically makes about 30 ATP per glucose.
If a fast growing cancer cell, a rare beast indeed, as most cancer cells are slow growers, can run glycolysis at more than 15 times the combined rate of glycolysis, Krebs cycle, and oxidative phosphorylation, then the fast growing cancer cell is kinetically ahead (ATP produced per unit time) just running glycolysis. Fast growing tumor cells can run glycolysis at more than 50 times the rate of the combined glycolysis-Krebs-OXPHOS of a normal cell.
Just as an overworked muscle cell must run glycolysis alone for ATP production, as OXPHOS cannot keep up (a KINETIC PROBLEM) with the oxygen demand, that is, ATP cannot be produced fast enough via glycolysis-Krebs-OXPHOS, a fast growing tumor cell needs to run glycolysis alone.