They have a ton of revenue and high gross margins. They burn billions because they need to keep training ever better models until the market slows and competition consolidates.
In this world, R&D costs and gross margin/revenue are inextricably correlated.
The market always consolidates when it matures. Every time. The market always consolidates into 2-3 big players. Often a duopoly. OpenAI is trying to be one of the two or three companies left standing.