Companies like OpenAI definitely have the resources to let some lawyers analyze the situation and at this point it should be clear to them if they can or can't do this. It's far more likely that they're holding back because of limitations in hardware resources.
I use those words because I've never read any of the points in the EU AIA.
They definitely do have the resources, but laws and regulations are frequently ambiguous. This is one reason the outcome of litigation is often unpredictable.
I would wager this -- OpenAI lawyers have looked that the situation. They have not been able to credibly say "yes, this is okay" and so management makes the decision to wait. Obviously, they would prefer to compete in Europe if it were a no-brainer decision.
It may be possible that the path to get to "yes, definitely" includes some amount of discussion with the relevant EU authorities and/or product modification. These things will take time.