That 2500 years of game play is reflected in chess theory and book openings, what you might consider as pre-training vs test time compute.

A human grandmaster might calculate 20-ply ahead, but only for a very limited number of lines, unlike a computer engine that may evaluate millions of positions for each move.

Pattern matching vs search (brute force) is a trade off in games like Chess and Go, and humans and MCTS-based engines are at opposite ends of the spectrum.