With disposable diapers, I found that I was going through steps 1-9 at least once a week. The diapers come in 40 packs. If my son averages 8 diapers a day, that is only 5 days. Sure, I can (and did) buy multiple 40 packs at a time, but I only have so much room at my house and in my car for transportation and storage. Moreover, especially when my son was younger, it was not uncommon for him to go through 5 diapers during a single night and he had a much fast diaper burn rate than even what I described above.

Your linked study seems interesting and I am reading through it.