[kimikimi]

Most of the interesting optimizations specific to the problem domain of games (e.g. JPS, Theta*) appeared after 2000.

Anyway, the path finding feature is not finished once you have a graph traversal solution. Routing large armies with formations, varying unit sizes, dynamic terrain and collision detection remains fairly challenging in practice.

[AstralStorm]

Indeed. But mostly due to engineering and time crunch, not because the algorithms are hard or unknown.