How Much Supercooling Survives a Maximum Density? Vacuum Domination Without Runaway

At a critical temperature of 100 GeV the vacuum density is only 8.38e-29 of the ceiling. Even complete vacuum domination in that epoch uses a negligible share of the permitted energy budget, and arbitrarily prolonged supercooling, were the tunnelling rate to allow it, would not bring the total near the bound. At a critical temperature of 10^8 GeV the share has risen to 8.38e-05, still small but twenty-four orders of magnitude larger, tracing the T^4 scaling. Only for critical temperatures within a few orders of magnitude of the ceiling temperature, 1.05e+09 GeV, does the vacuum share approach unity and the bounded budget become the operative constraint on how a supercooled history can be written. This study is simulated and computed from stated assumptions; it is not a measurement.