For one potential path - Less datacenter construction means less GPUs, so less $$$ for Nvidia, which means less for them to spread around to prop up the LLM industrial complex, which means lower valuations, which means OpenAI and Anthropic can't get their trillion dollar valuations, which means VC's race for the exit to cash out, etc, etc.
The housing bubble was people borrowing money (debt-fueled) to buy ever more expensive houses (rising asset prices) on the assumption home values would always keep going up (projection of future value).
'90s tech bubble was similar.
Where are you seeing that now? Which asset is over-valued?
OpenAI and Anthropic are not very profitable (yet!), but rely mostly on equity financing, not debt. So no debt load issue there either.
What is NVIDIA's outlook should their customers' funding run out? Or what's the long tail outlook on Google killing its search product?
OpenAI and Anthropic not making money would be sad for their shareholders, but that's sort of a different topic from whether the "debt load" you originally cited will be any kind of a systemic problem (it won't).