I agree. If Albert Einstein had gone with your sensible approach he could have quickly ruled out his silly idea of relativity as impossible and gone back to his more important work of approving patent applications.
In the case of LLMs I would say that VC funding made the engineering possible. The theoretical breakthroughs were largely made in IBM and Google. OpenAI certainly made some improvements to architecture and training, but ultimately they implemented a refined version of a transformer-based LLM.