yeah but 1) its useful to have the point there on the curve if you need it, 2) intelligence is multidimensional, maybe in 2.5 flash you get qualitatively a better set of capabilities for your needs than 2.5 pro

It does, that point in the tradeoff space was not available until now. Any model that's not dominated by at least one model on both axes will push forward the frontier. (The actual frontier isn't actually a straight line between the points on the frontier like visualized there. It's a step function.)