I use it as a generalized example because pushups come with their own built-in variations. The progression for trainers and physical therapy is usually box pushups (hands on box) with setting a ~20% weight supported (i.e. equivalent of a decline press of a low weight). Once repetition targets can be hit on that it'd transfer to a lower box (turn on side) for closer to ~30% of weight. Again on lowest box setting for close to 40% of weight. Then pushups from knees (some will do this before the final box setting). Then regular pushups. Then pushups with feet elevated on the box, progressing back up on box height. Finally mixing in advanced techniques such as hand placements, offset objects like medicine balls, etc.

In my initial example, yes it was too simplified, but to more point out that resistance training need not be always externally load dependent. I'm simply a big fan of people committing to any resistance training program they enjoy enough to stick with for several months at a time.