Perhaps never before in American history has one person held as much power and influence over as many critical industries as Elon Musk.

Why it matters: Musk is shaping the future of transportation, communication, artificial intelligence and space — an enormous, maybe even unprecedented concentration of power and influence. How he wields it — and whether he can get out of his own way — affects the whole world.

Zoom in: 2023 was a dramatic year for Musk, his companies, and, as a result, the industries they occupy and several big-picture scientific and geopolitical endeavors.

In space, Musk is perhaps the most important single figure to the United States' ambitions since Wernher von Braun, who revolutionized rocket science after World War II, Axios' Alex Fitzpatrick writes.

• SpaceX now gets astronauts to and from the International Space Station as reliably as a daily mail delivery
• It’s also a critical provider of commercial satellite launches — including for the Pentagon.
• Ukraine has relied heavily on SpaceX's Starlink satellites — no other CEO in the world could have singlehandedly cut off such a vital communications tool in the middle of a war.

SpaceX's still-in-development Starship rocket — the most powerful ever built by human hands — is a key element of NASA's ambitions to put American boots back on lunar soil this decade.

• The company also has ambitions to use Starship to get to Mars — and potentially beyond — as park of Musk's lofty mission to turn humanity into a "multi-planet species."

In the auto industry, Tesla this year pioneered a process called "gigacasting" that his competitors are already trying to replicate, Axios' Joann Muller writes.

• The process lowered the cost — and improved the profitability — of its best-selling Model Y.
• Instead of welding hundreds of smaller parts together to build a conventional car's underbody, Tesla uses huge, house-sized machines to mold the front and rear structures. Then, it joins the two pieces together.
• Rivals are now scrambling to catch up. Even Toyota, long known as the leanest auto manufacturer, is adopting Tesla's gigacasting process.

What to watch: Tesla is on the edge of a further breakthrough that would extend its lead — die casting nearly the entire underbody in one piece, Reuters reports.

• Slashing production costs will enable the industry's holy grail: a $25,000 electric car, making them far more accessible and accelerating the shift away from gas-powered cars — a major dent in the No. 1 source of greenhouse gas emissions.

Musk is also leaving his mark on the internet, with his purchase of — and antics on — X, formerly known as Twitter, Axios' Javier E. David notes.

• This year, we saw that Musk may ultimately kill the platform he loves using — as his actions triggered an exodus of major advertisers, including big names like Apple and Walmart.

X's dominance as a source of news and information may be slipping, and Musk's antics on the platform may put the rest of his empire at risk, Axios' Hope King writes.

• Case in point: Tesla is still one of the most valuable companies in the world, but that valuation has taken direct hits as Musk's obsession with X and his own questionable speech on the platform push investors to rethink their support.

Zoom out: Musk keeps undercutting his undeniable role as a reshaper of industries with his penchant for bizarre, quixotic products and his courtship of extremism and hate speech under the banner of free speech, Axios managing editor Scott Rosenberg writes.

• Presumably there are customers out there who find the Tesla Cybertruck — which critics likened to a refrigerator on wheels — attractive. But how many?
• X has now welcomed back conspiracy theorist Alex Jones, along with a slew of white supremacists, racists and Nazis — a good number of whom Musk himself happily replies to and retweets.

The bottom line: Reshaping the way things are done in the industries driving the future is one kind of hard that Musk excels at.

• But dealing with a complex human society is an order of magnitude harder, and Musk's powers seem to fail him whenever he leaves the factory floor for the broader social arena.

Go deeper: Elon Musk to advertisers boycotting X: "Go f**k yourself"