On any closed hyperbolizable 3-manifold, we find a sharp relation between the
minimal surface entropy (introduced by Calegari-Marques-Neves) and the average
area ratio (introduced by Gromov), and we show that, among metrics g with
scalar curvature greater than or equal to -6, the former is maximized by the
hyperbolic metric. One corollary is to solve a conjecture of Gromov regarding
the average area ratio. Our proofs use Ricci flow with surgery and laminar
measures invariant under a PSL(2,R)-action.Comment: 30 pages. Final versio