Yes, this is a problem with modern AI systems in general. It's not just OpenAI, and if you know any artists you know this is why they're pretty vehemently opposed to all AI.
Google docs exists as a competitor to microsoft office. Google gives it away free to consumers for the same reason AI labs sell subscriptions for 10% of the price of the api. They hope businesses will switch to what employees know how to use.
What? I don't understand how you even came up with this idea, much less consider it so obvious to condescend about it. Do you have even a single example of a research project that got scooped because the Google Docs team forwarded their private documents to someone?