massive drop in revenue expectations

This is still future predictions.

The pop happens when the bonds cannot be repaid.

On September 21st OpenAIs sponsor, BB+ issuer Softbank, placed an $11 billion single bond sale to fund an AI infrastructure bet, and it was oversubscribed.

The bubble is still inflating.

It hasn't been people hoping. There are quite a few analysis papers out there doing the math of the impossibility of achieving profitability of the current US model. Chinese models offering equivalent performance for 10x lower cost, and near frontier level open weight models to run in house for the cost of the hardware, and this hardware being way more modest, makes the bubble pop a certainty. As with data loss, the question is when, not if.