How does a Dyno Really Work?

67Dart273 claims it's a myth cause it can only be calculated and many have also implied the cause it's calculated that it's of lesser importance. I know you/others don't overly care it's a pet peeve of mine and since it's the bases of performance it's shouldn't be misunderstood as it is.

Performance = power to weight, since most of the cars were talking are similar weight it comes down to power and how well you apply it. (Job)

Power = some kind combination of rpm and torque, mainly based on hp (top end), tq/cid (efficiency) and displacement. (How you go about getting that Job done)

Don't know why some insist on a hp vs torque dynamic, shouldn't be at that controversial,
Hp is tq and rpm no "VS". You could argue which way to make X HP, RPM vs TQ which I think people kind of mean when they say hp vs tq.