I really really wonder how the price of vertex.so compares - in practice - to the openai api for use by a startup with unpredictable and non-sustained usage???

I really really wonder how the price of vertex.so compares - in practice - to the openai api for use by a startup with unpredictable and non-sustained usage??? The multitenancy assumptions that are part of the openai api cost structure might make it much cheaper. Has anybody modeled this? I realize the LLM’s aren’t equivalent today, but longterm they could be.