A human dances in booth at a generative AI art exhibitionNurPhoto/Getty ImagesBig tech is spending $1 trillion on generative AI.Generative AI won't scale as well as old-school software businesses.RBC analysts see GenAI leaving software profit margins 'structurally' lower.Amazon, Microsoft, and Google spent more than $48 billion in the second quarter, mostly on data centers, according to Synergy Research Group.Big tech companies are forecast to spend an eye-watering $1 trillion on this stuff.