Einstein didn't know about the real, massive, particle potential of the quantum vacuum, or he never would have abandoned this finite "quasi-static" cosmological model, because there is no instability when matter generation from the negative energy states drives vacuum expansion, because this "anti-gravity" effect is obviously offset by the gravity of the newly created massive particle, and that makes all the difference in the world to the Dirac Equation, which can be reformulated in this vacuum as it was originally intended, to unify General Relativity and Quantum Theory, as Paul Dirac did with SR and QM.
This leads to a new cosmology that predicts that increasing tension between the expanding vacuum and ordinary matter is what eventually causes the forces to be compromised, aka., "big bangs", so there is no need for a naked singularity, nor extra-ordinarily rapid inflation when a universe with certain volume "evolves" information inherently forward to a higher order of the same basic configuration.
Our Darwinian Universe
Physics for the prediction is discussed briefly, here:
And in greater detail, here:
Challenge Richard A Ryals to a bet on this prediction!