steady state isn't equilibrium

A living cell can look perfectly calm while being nothing like a glass of water sitting still, because it holds that calm only by burning energy without pause to keep from falling apart. The chemical engineer's way to say it is that the cell sits at a steady state, not at equilibrium, and those are very different things.

\[ \begin{aligned} \frac{dC}{dt} &= \underbrace{\tfrac{q}{V}\,(C_{\text{in}} - C)}_{\text{transport}} \;+\; \underbrace{r(C)}_{\text{reaction}} \\ \text{steady state:}\ \ \frac{dC}{dt} = 0 \;&\Rightarrow\; \tfrac{q}{V}\,(C_{\text{in}} - C) = -\,r(C) \neq 0 \\ \sigma = \frac{A\,v}{T} \,\ge\, 0, \qquad A &= -\sum_i \nu_i \,\mu_i \\ \text{equilibrium} \;&\Leftrightarrow\; A = 0 \;\Leftrightarrow\; \sigma = 0 \end{aligned} \]

C is a concentration inside the cell, q/V how fast it's flushed and refilled, C-in what flows in, and r(C) the reaction rate. at a steady state the concentration holds perfectly still (dC/dt = 0), yet the transport and reaction terms are each large and just cancel, so matter and energy pour through the whole time. sigma is the entropy the cell produces, set by the reaction's driving force, its affinity A (the stoichiometry-weighted gap in chemical potentials, with nu the stoichiometric coefficients and mu the chemical potentials) and the rate v, divided by temperature T. away from equilibrium A isn't zero, so sigma stays positive and the cell has to keep paying energy to hold its state. only at equilibrium does A go to zero, the flows stop, and sigma vanishes.

Real equilibrium, for a cell, is death -- the state it settles into once it stops fighting.

The most stable-looking things around you, a healthy body, a working company, a calm temperament, are usually the most expensive to keep that way, held in place by a lot of work you never see.