So far as I'm aware, we don't know that inference for free users is counted as cost of revenue as opposed to sales and marketing.

With sales and marketing at 5.7b, which seems unusually high compared to cost of revenue, I think it's deeply irresponsible to ignore that when considering how profitable OpenAI may be. Even taking a charitable interpretation, OpenAI is having to spend considerable budget (more than their gross profit!) to keep people paying for using their services. The less charitable interpretation is that they're deeply unprofitable and they're pulling every legal accounting trick to hide the sources of unprofitability.