The Tim Cook era is coming to a close with an existential challenge for Apple: figuring out what comes after the iPhone.

Why it matters: Cook extended the iPhone's success into products like the Apple Watch and AirPods and built a powerful services business. But the company hasn't broken into a major new category — and has stumbled into the AI era.

Driving the news: Apple announced yesterday that Cook will cede the CEO reins to hardware expert John Ternus, while remaining as executive chairman.

• The company also promoted Johny Srouji, the driving force behind Apple's chip success, to the new role of chief hardware officer.

The big picture: Cook has executed masterfully to maximize the company's iPhone success and transform Apple into one of the world's most valuable companies.

Yes, but: His efforts to expand far beyond that device have largely sputtered.

• The company assembled a significant team to try to enter the autonomous car market, but gave up before bringing anything to market.
• The company's initial foray into the mixed reality market, Vision Pro, remains for sale, but at a price that has attracted relatively few buyers.

Zoom in: Apple's position in AI remains uncertain.

• In 2024, Cook painted a compelling vision for Apple Intelligence, personalized AI that would be able to answer questions from data stored in a variety of places, but do so in a way that would not be accessible to Apple or anyone else.
• Apple has struggled to turn the vision into reality, repeatedly delaying the most ambitious features outlined in that keynote.
• A revamped Siri with some of those capabilities is expected later this year.

Flashback: Ternus laughed off the idea that Apple should worry about being late to generative AI in a 2023 interview, Bloomberg reported last month in a piece about his likely promotion.

• But he "knows he needs bolder products and a strong approach to AI."

The other side: Apple's restraint could pay off if it can maintain its hardware advantage, while others spend heavily on AI models, as Axios' Dan Primack outlined last week.

• While most of its tech giant peers have spent billions of dollars on data centers and compute capacity, Apple has avoided such large outlays.
• If the AI models turn out to be a commodity, Apple may look the wiser.

Emily's thought bubble: Hardware expertise is an asset in an era of shifting geopolitics and fragile supply chains.

• None of the AI companies have yet come up with an AI-first product with any kind of broad appeal.
• Analysts and investors have wondered what comes after the iPhone for a long time.

Shot: When Cook took over at Apple, some analysts wondered if he had the chops to fill the shoes of legendary CEO Steve Jobs.

Chaser: Cook increased Apple's market cap 12-fold. It's gone from about $330 billion to $4 trillion today — and is the third-largest American company by that measure, after Nvidia and Alphabet.

What to watch: Similar questions are now being asked about Cook's successor.

• Ternus is 50, the same age as Cook when he got the job — and yet another Gen X tech CEO.

Workers have never been more dissatisfied with their pay or their ability to get ahead. But the likelihood of moving to a new employer is at multiyear lows.

• Those are the bleak findings from a New York Federal Reserve Bank survey, which showed plummeting job satisfaction alongside diminishing odds that workers will be able to make a change.

Why it matters: For most workers, switching jobs is the fastest route to a raise or a promotion. But with hiring at historically low levels, that path has all but disappeared.

• The results have implications for consumer spending and productivity. A stuck, underpaid workforce might be less likely to spend freely and more likely to be less engaged.

By the numbers: The share of workers who said they were satisfied with wage compensation fell 3.3 percentage points, to 52.3% in March, the smallest share in the survey's 12-year history.

• The New York Fed surveys consumers' labor market expectations every four months.
• A related indicator, which measures workers' satisfaction with promotion opportunities, fell by a similar amount to the lowest share on record.
• The only satisfaction gauge above record lows: non-wage benefits.

The intrigue: Record dissatisfaction is not accompanied by plans to exit, at least not in the near term.

• On average, workers see decreasing odds that they will have a new employer in the next four months: The likelihood of such a move dropped to 9.7%, the lowest since March 2021. (Coincidentally, that was when wage satisfaction was at its peak in this survey.)

The other side: Workers assigned slightly smaller odds that they would be fired in the next four months — about 3.4%, down two ticks from February.

• Workers are still bidding up pay expectations. The average reservation wage — the lowest wage respondents would be willing to accept for a new job — hit a survey high in March, an increase driven by male workers and respondents with a college degree.

The world's largest data center project is stalled by delays and logistical hurdles that could stop it before it even starts.

Why it matters: Fermi's Project Mastodon, a massive combination data center and power generating campus bearing Trump's name, is a high-profile test of whether the biggest, most ambitious AI infrastructure projects can deliver on their promises.

• It's not going great.

Catch up quick: The latest sign of trouble emerged Friday when CEO Toby Neugebauer abruptly departed.

• In an interview with Axios just the day before, he had given no indication that he was about to leave.

Zoom in: The company's shares, which already shed 75% in the last six months, sunk further.

The latest: By yesterday morning, the company announced a "Strategic Evolution," talking about Fermi 2.0.

Between the lines: Fermi hasn't been able to get any companies to sign on as customers.

• You know the saying, too big to fail? Well, this project might be too big to succeed — the proposed campus spans a space half the size of Manhattan with three times the power demand of New York City, according to Neugebauer.

The intrigue: Bloomberg's Liam Denning puts it thusly: "The Fermi Paradox asks why, given the vastness of the universe, there is no hard evidence of aliens," he writes.

• "The Fermi Inc. paradox asks why, given seemingly insatiable demand from hyperscalers for electricity, former Energy Secretary Rick Perry's AI-energy firm hasn't obtained a hard power contract from said hyperscalers."

Go deeper: Trump-branded AI data center megaproject stalls, CEO departs