Almost every athlete wants to play at the top level, Rom included. I'm not condoning how he's gone about it, however place yourself in his shoes. He's one of the best strikers in the world and he's at a club who finished 11th in back to back seasons and are about to finish 7th. As a professional it's acceptable for him to aim for the highest level, and highest wages. Nothing wrong with wanting to earn more money in your career.
You're right, he might go to Man United who offer him astronomical wages with no CL football, but they're on track to gain CL football in the next couple of seasons and will attract huge names to help them get it. In the next 3 years would you be surprised to see them battling for the league with Morinho in charge along with more huge name signings? I wouldn't.
I don't think he would go to China for 500k+ a week. I genuinely think he wants to play at the top level.
How do you expect him to react? "I'must happy here battling for Europa League football?"
Not a chance.