The unobtainables are highly sought after by collectors.

The goal seemed unobtainable, but she never gave up.

The perfect life is often seen as an unobtainable goal.

The unobtained prize left her feeling disappointed.

The unobtainability of happiness is a common theme in literature.

The unobtainableness of the rare gem made it highly sought after by collectors.

The rare gemstone was unobtainably expensive.