Stripe had high variable costs (staff, COGS of pass-through processing fees) but low fixed costs. OpenAI has enormous fixed (pre-revenue!) costs alongside high variable costs (staff of AI engineers, inference).

Financially, OpenAI looks more like one of the EV startups like Tesla or Rivian than it does a company like Stripe. And where Stripe was competing with relatively stodgy financial institutions, OpenAI is competing with the very biggest, richest companies in the world.