Looking across the biosphere one finds a distribution of lifeform complexities. (In the absence of things like mass extinctions) this distribution TENDS to broaden with time. The extreme tail of such a distribution then also increases with history, i.e., the maximum complexity of organisms TENDS to increase (but DIFFERENT organisms will be at this extreme peak at different moments.) (AGAIN, the biosphere is an open system, we are neglecting such things as mass extinctions here.) Today humans are up in the tail of this distribution of complexities. Perhaps when humans become extinct our machines may survive us and occupy such a position.
Complexity will likely not be maximized by the same lifeform that maximizes longevity. Again, "progress" is likely to be measured by vector quantities.