what revenues? If by big AI companies you mean llm service providers (OpenAI, ...), their revenues are far from high or profitable. https://www.cnbc.com/2024/09/27/openai-sees-5-billion-loss-t...

Maybe Nvidia, but they are a chip / hardware maker first. And even for them 50B training run with no exponential gains seems unreasonable.

Better to optimize the architecture / approach first, which also is what most companies are doing now before scaling out.

It's not unusual to make infrastructure investments that will pay off in 30-50 years. I don't see why not an AI model - unless it's not true that we're at the end of scaling.