"What do you mean by ‘alone’?"

I mean one person can personally mine the ore, smelt it, and make iron from it. https://primitiveskills.net/primitive-skills-making-steel-from-iron-ore/

The video shows how he does it by himself, mining the ore, building the furnace, and smelting the iron, starting with sticks and stones.

"...you'd have to convince young people to educate themselves in all these matters like agriculture, transportation, communications and construction."

When I was young all I wanted to do was get out of the woods, into a city, and party. As people live they change, as you have changed. When they get old they will disparage the youth of their day just as Plato did the youth of his day ("...someone who’s a bit older… will refuse to have anything to do with this sort of idiocy..."--Plato, The Republic). I understand your point that we cannot simply abandon civilization and recreate it from scratch. I tried to show how the formerly exclusively massively centralized electronics industry is decentralizing, with individuals being able to manufacture custom made devices today, while it used to be necessary for a massive corporation like Sony or Phillips to assemble all the tooling and expertise to do so. The end point of a journey isn't any of the steps taken towards it, and the development of tools that an individual can personally own that automates all the processes necessary to manufacturing electronics isn't at hand, or soon to be.

However, that total and complete decentralization of all production isn't the tipping point after which sybaritic overlords become unable to reverse the trend towards decentralization, and that's not the point at which overlords are reduced to making their wealth themselves and can no longer profit by hiring laborers. Decentralization proceeds one step at a time, and each individual or small company/community that undertakes to produce some good or service themselves does so to increase their wealth, and their retention of their production that creates their newfound wealth deprives corporate investors of dividends and relatively reduces their wealth compared to the plebs.

"I just don't see anyone near me and I know no one in person who does such things. Do you?"

You do know people that are making themselves products they use themselves that they do not incur tax liability for making nor provide corporate investors dividends/profits. You aren't thinking of people splitting firewood and heating their houses from trees they grew, or picking wild berries and canning their own jams and jellies, as I just have, or knitting sweaters and caps. I am trying to point out that something isn't either decentralized completely or isn't decentralized at all, but that decentralization is an ongoing transition driven by the laws of physics that mandate dispersing production across populations increases productivity because further centralization doesn't, for various reasons, such as increasing waste, diminishing returns on capital investments in tooling, and etc.

I have made a sign for a local trailer park, with very attractive lettering routed into robust planks of wood with great precision. This was possible because the computer controlled router is now available at a price a local craftsman could afford, and he actually has a business making signs, artwork, and cleverly machined puzzles and the like. Formerly such work required very expensive tools far beyond a simple craftsman's reach, or great skill and patience with hand tools. Similar tools enable machining metals and precision manufacturing of firearms, complex automobile and boat parts (I live in a fishing village), and other tools enable additive manufacturing of household items such as the plastic bits and knobs that break or fall off of things, of clays and pastes, and I've seen experiments with folks 3D printing with molten glass. This may seem edgy and inconsequential, but so did the first automobiles or steam turbines, in their inventors garages.

Each table top cnc machine, 3d printer, or tilapia tank and lettuce shelf fed on the fish waste is an advance of decentralization and decrease in centralization, and this distribution of such tools across the population is happening increasingly fast as the benefits of doing these things increases in value due to inflation, and the tools improve and develop. All these single points of decentralization are cumulative, impacting individuals, communities, and the world economically - and permanently. We didn't get to the current Western civilization of a sudden, but over centuries of development, and while it won't take centuries to decentralize industry, it began decades ago when Stanford and MIT envisioned the Fab Lab, and will take decades more before that tipping point beyond which the process is irreversible occurs. Until then sybarites will desperately seek to prevent that from happening, because they really like their luxurious wealth and want to keep it.