Don't get me wrong. I agree with you: Robert is a great Tony Stark. He is definitely Tony Stark. His portrayal of the character will be considered to be the best. No doubt about that. However it doesn't mean that whoever will replace him some time in the future can't do as good a job as him. It doesn't mean his Tony Stark/ Iron Man will not be as good as Robert's. Before you criticise a new actor's portrayal of Tony Stark/ Iron Man you need to see it. You can't form an opinion on something without seeing it. You might be right but you might be wrong as well. You might be pleasantly surprised. You never know.
I said he was full of himself because he thinks nobody else could step into his shoes. I said that because I was shocked by his statement. I thought: 'why did he say that? How does he know nobody else can play Tony Stark?. 'He thinks he is irreplaceable. He sounds arrogant to me. That's not like him, because anybody who has met him says he is a nice guy.