I noticed that strong players often discuss openings in the following terms: "this is an ideal setup in this opening", or "this play in opening X is bad because all you get is a worse version of opening Y". In other words, an extremely useful way to evaluate a position is to compare it to some benchmarks. However, when studying openings, it is often hard to pinpoint what are these "ideal setups" and why they are ideal. GMs will never allow each other to get a dream scenario, so studying their games does not help. Ditto for theoretical lines. So, I always feel that I'm studying shadows on a wall, while these platonic "ideal Ruy Lopez" or "ideal French" never appear explicitly.
What are some good ways/resources to fill these gaps? Is it useful to study games by lesser players who allowed this "ideal French" appear on the board and lost in an instructive way? Are there collections of such games? There are many collections of "miniatures" in which one side falls for a trap, and often a master is known solely for being defeated in this miniature. But what about collections of games where black loses on move 50, but was doomed by move 15 because they allowed white to put their pieces on all best squares and execute their dream plan? Or are there books that focus on this aspect?