It very much is a basic technique you learn in analog circuit design (or at least it was 30 years ago when I was in school). Similarly, there are circuits (like that current mirror) which rely on the nonlinear behaviors of diodes or transistors varying in sync — you can build them on the same chip, or you can carefully select matched sets from one manufacturing run.
An example with resistors is a voltage divider. The output voltage depends on the ratio of resistances not on the absolute values (within reason). The resistors in a long-tailed-pair also need to be matched but their precise value is less important. Or you might have a bias current that's temperature-dependent but in a way that matches the temperature-dependent needs of some other bit of circuitry on the output.
There's a famous early integrated opamp which has a four-way-symmetrical die layout to compensate not only for temperature variations across the die but also process variations.
An example with resistors is a voltage divider. The output voltage depends on the ratio of resistances not on the absolute values (within reason). The resistors in a long-tailed-pair also need to be matched but their precise value is less important. Or you might have a bias current that's temperature-dependent but in a way that matches the temperature-dependent needs of some other bit of circuitry on the output.
There's a famous early integrated opamp which has a four-way-symmetrical die layout to compensate not only for temperature variations across the die but also process variations.