> which would take longer than the heat death of the universe to find the global maxima

Sure, if you're using brute force, instead of a polynomial time algorithm.

> It doesn't matter what algorithm you use, finding the absolute best solution and proving it is impossible.

Hard disagree: https://en.wikipedia.org/wiki/Hungarian_algorithm

Linear Assignment seems a very strange choice to illustrate the utility of meta-heuristics, when that particular problem has a polynomial-time solution algorithm that has been known for 70 years.