> It's hard for me to see this being bigger than the great recession unless there's some vulnerabilities in the banking system we're not aware of.
The scenario I see is write-offs. At the moment there are hundreds of billions in IOUs being passed around, much more in liabilities than Lehman had back then in 2007. Compounding that is the frankly insane valuation - it's as clear as day that at least one of the major AI shops will go bust, they all run at a (huge) loss and sooner or later, one of them will run out of cash before achieving market dominance.
Unfortunately, OpenAI and Anthropic are valued at almost 1 trillion $ - backed by nothing but the hope on the winner surviving and achieving the classic VC-backed near-monopoly. The staff can be poached, they don't hold much in IP like patents, the servers and GPUs are mostly owned by third parties like AWS, Microsoft, Google or Oracle - once the cash runs out, they can't sell any assets for even some runway extension because there are no assets. Even the model weights and training data aren't worth much - all competitors already have training data sets of their own, it does not make sense to acquire further data, and model weights are being rendered obsolete by the constant churn of open-weight models particularly from China.
SpaceX is valued even higher, but unlike the other two candidates, they still at least got a viable business even if the entire AI BS bubble collapses, Starlink is a money printer and there's no alternative in sight that matches SpaceX and their reusable rockets.
Now, if either of the three even experiences a large drop in valuation for whatever reason, it's not just experienced VCs that can readily afford (and expect) investments to fail, but this time a lot of "everyday" investment vehicles (such as pension funds) will have to issue write-off losses, and now that they are publicly traded, that may also trigger stop-loss cascade orders further dropping prices, and retail investors will probably join in on the mass panic. That's the #1 risk IMHO.
The #2 risk is that after a collapse, the service providers (i.e. the ones owning the servers) will be sitting on a ton of hardware that has nowhere near recouped its cost. AWS, MS and Google can probably repurpose most of the hardware for their own use and rent out what remains, but they will have to eat significant accounting losses, provoking again a drop in their stock price, but this time with even more blast radius as all three of them are established stock index (and thus ETF) members that a looooot of people have exposure to. But someone like Oracle? They might actually get fried for good.
And the #3 risk is further downstream, particularly relating to NVDA. They have enjoyed years of insane profits because they are the only ones making high-performance AI chips. When demand for new chips collapses due to the event(s) I just described, they can easily shift their TSMC production slots back to GPU wafers and sell these to gamers - but at a far lower profit than before, which again can trigger stock price drops and write-offs.
I won't go further downstream - TSMC and their suppliers are IMHO pretty safe because there is just so much pent up demand from everything not AI, and the construction companies building datacenters don't have too much of a blast radius when the big guns stop expansion projects.
The concrete scenario I'm really, really afraid of: all three succeed with their IPOs, maybe they all survive a year and get included even in S&P 500. The existing shareholders and insiders all slowly dump a lot of their vested stock onto the public market, which in cleartext means into the dozens of billions of $ of retirement contributions. One day, the bubble bursts for whatever reason. The stock markets drop in a panic sell-off, either triggered by stop-loss orders or because retail investors are a herd of sheeple (just like in the 1st covid lockdown). Eventually, circuit breakers on the stock markets will trigger (just like they did in the GME post-apes collapse) and trading will pause, but it will resume until the markets have adjusted to the new valuation... and once the dust clears up, there will be a lot of blood on the floor. Possibly even riots, depending just how much retirement assets just got wiped out.