This is a pretty well done article. Here's some general ideas to keep in mind.
- Most dismounted missions are run from trucks or an established forward operating base, so you don't carry a huge rucksack most of the time because you can just go back to your base.
- Like the article states, even a day pack with body armor gets you up to 70lbs quickly.
- Ammo is really heavy, it being made of lead and all. 100rds of 7.62mm ammo weighs about 7lb. You want at least 800rds per M240B.
- Rucksack weights are sometimes inflated because it's a way to brag.
- The Marine infantry officer course requirement for 152lb load is excessive. At that weight, you can only do an admin movement on a road. All the anecdotes I found about combat loads that heavy were for an initial, short infil followed by a stationary mission.
I think the article nails the root cause towards heavier protective equipment. Public perception and the news cycle makes the death of American service member a bigger deal than in past conflicts.
It will be a long time before we get electronic mules in the Infantry. Adopting the mules adds a huge complexity budget to a simple movement. The Army decided some years ago to give every Company (~140 people) a Raven drone for recon. However, it's a huge deal if it gets lost (if the GPS guidance were to suddenly fail), so no one ever uses them to avoid the fallout associated with losing Army equipment.