Clever marketing, I suppose you could call it, but I remember the first time I realized that a cap full was not necessarily the recommended amount of detergent per load. I felt a little bit ripped off. It's kinda like finding out that half a bagel is a whole serving. Or half a bottle of Snapple.
Here's the proof. In my case, the 51 load bottle would have been more like a 21 load bottle. Check it out.
Here are the instructions
And here is the line for the "small to medium" loads
I drew it on with a Sharpie to help me retain my eyesight -
the bar is not exactly obvious, for some reason.
So, whether you're doing the laundry, or trying to figure out who to vote for, I suppose it's better to read up on the facts rather than just doing as you've always done or making assumptions. In the laundry department, the soap goes twice or three times as far.