What are these bumps on the top of a pull-tab can?

The difference is something like phone ports and docking are things which end users readily benefit from having interoperability, so it's a selling point and there's market pressure to conform. Factories are bespoke installations and they often run without major changes for many years at a time. There's less pressure for them to have interchangeability when they don't move and don't interact with each other.

Still, bauxite is pretty weird business.

If the Brazil plant is putting out enough ore, I can definitely imagine it is cheaper to sell it internationally to someone with hydro power than to build and operate their own power plant.

Inversely, those folks that think about how things work tend to be fairly overconfident in their ability to recreate/repair/innovate. In reality there are often fine details that you miss.

Of course people can learn anything. It's that we tend to not realise that we don't know this stuff, and so we underestimate the difficulty/complexity of them. This often leads to people actually looking down dismissively on other people's jobs, as they assume they must be simple or easy, because they have never done them. You get endless political commentry on how people doing certain jobs don't deserve to be paid well because what they do appears "simple". Train drivers are a classic example. It's a job that is a lot harder and more involved than it appears at first.

For a while I worked in the rail industry. That was full of things that were way more complex and involved than I had ever realised. Things that seemed simple on the surface had decades of refinement and subtlety to them born of experience.

Your example is a great one. The principals of the flushing toilet with a siphon flush, ballcock and an S-bend outflow are not complex, but a lot of people have no idea what pressing a flush down actually does to get the water into the bowl, how it refills or what the S-bend is actually for (it's more than just the smell, sewer gas is explosive). It's the reason that a lot of people don't tackle more DIY jobs, they suddenly realise they don't understand it. But it's also why YouTube is so great, because these things are all learnable.

In the event of a societal collapse, I sometimes think that preserving all the instructional YouTube videos would be our best hope for rebuilding :D