Perhaps he's got his eye on usurping next season? Perhaps he likes it in London? I dunno.
But based on Wenger's quote, it does seem the promise of CL football has made the difference.
I reckon there's a more than reasonable chance Ospina was persuaded to stay by Wenger offering him CL football. I'm sure the FA Cup didn't do any harm, either.
So no I don't think I'm correct because I can't know for sure. But I think it's a reasonable and not at all outlandish guess.