There is no doubt that OpenAI is taking a lot of risks by betting that AI adoption will translate into revenues in the very short term. And that could really happen imo (with a low probability sure, but worth the risk for VCs? Probably).
Apparently we all have enough money to put it into OpenAI.
Some players have to play, like google, some players want to play like USA vs. China.
Besides that, chatting with an LLM is very very convincing. Normal non technical people can see what 'this thing' can already do and as long as the progress is continuing as fast as it currently is, its still a very easy to sell future.
Correction: OpenAI investors do take that risk. Some of the investors (e.g. Microsoft, Nvidia) dampen that risk by making such investment conditioned on boosting the investor's own revenue, a stock buyback of sorts.
It's mathematically impossible what OpenAI is promising. They know it. The goal is to be too big to fail and get bailed out by US taxpayers who have been groomed into viewing AI as a cold war style arms race that America cannot lose.