The current AI spending spree by tech giants is historically reminiscent of the railroad and fiber-optic bubbles. These eras saw massive, redundant capital investment based on technological promise, which ultimately led to a crash when it became clear customers weren't willing to pay for the resulting products.

The current AI investment surge is a dangerous "resource grab" phase, not a typical bubble. Companies are desperately securing scarce resources—power, chips, and top scientists—driven by existential fear of being left behind. This isn't a normal CapEx cycle; the spending is almost guaranteed until a dead-end is proven.

The AI buildout won't be stopped by technological limits or lack of demand. The true barrier will be economics: when the marginal capital provider determines that the diminishing returns from massive investments no longer justify the cost.

The massive investment in AI infrastructure could be a narrative designed to boost short-term valuations for tech giants, rather than a true long-term necessity. Cheaper, more efficient AI models (like inference) could render this debt-fueled build-out obsolete and financially crippling.

The massive capital rush into AI infrastructure mirrors past tech cycles where excess capacity was built, leading to unprofitable projects. While large tech firms can absorb losses, the standalone projects and their supplier ecosystems (power, materials) are at risk if anticipated demand doesn't materialize.

The AI boom's sustainability is questionable due to the disparity between capital spent on computing and actual AI-generated revenue. OpenAI's plan to spend $1.4 trillion while earning ~$20 billion annually highlights a model dependent on future payoffs, making it vulnerable to shifts in investor sentiment.

Historical technology cycles suggest that the AI sector will almost certainly face a 'trough of disillusionment.' This occurs when massive capital expenditure fails to produce satisfactory short-term returns or adoption rates, leading to a market correction. The expert would be 'shocked' if this cycle avoided it.

The current AI investment boom is focused on massive infrastructure build-outs. A counterintuitive threat to this trade is not that AI fails, but that it becomes more compute-efficient. This would reduce infrastructure demand, deflating the hardware bubble even as AI proves economically valuable.

The common goal of increasing AI model efficiency could have a paradoxical outcome. If AI performance becomes radically cheaper ("too cheap to meter"), it could devalue the massive investments in compute and data center infrastructure, creating a financial crisis for the very companies that enabled the boom.