I had an epiphany.
"What is dark energy?"
Accelerating expansion is a product of the stability of the true vacuum. Dark (phantom) energy is essentially the enforcement of the stability of the vacuum. It is like we are in violation of that stability and the big rip is our cosmic punishment.
Sean Carroll mentions "If the universe is eternal, and has an equilibrium state, we should be in that state, but we are not." Similarly, in principle the ultimate stable state is the perfect vacuum. I realize nature seems to disagree in ways, but as a rule empty space remains empty. Energy is neither created nor destroyed. Nothing can come from nothing.
So as the universe expands, in the later stages it becomes increasingly cold and empty, and as the universe approaches nearer to becoming a true vacuum, the dark energy density increases and the expansion rate accelerates in order to establish the absolute stability of the true vacuum.
The universe should be in a stable condition, the vacuum, but isn't. So the vacuum in a sense enforces its law of stability. Dark energy enforces the law of stability by accelerating the universe into a state of being perfectly flat. From our perspective we see expansion accelerating but once space is inflated, once time reaches absolute zero, there is just perfect symmetry, a space that extends infinitely in all directions. There are no quantum fluctuations or virtual particles in the true vacuum since in reference to ordinary matter density space is inflating. In actuality the true vacuum is simply a fully inflated space, a full four dimensional space.
If we start with an absolutely stable true vacuum we can expect a force of resilience against instability, or let's call it a dark energy density that is infinitely strong, that simply maintains or is the stability, just as gravity
"is" the curvature of space-time.