Yes, we become new. But I know of no one for whom it has been an overnight success. The renewing of our minds, the dying of the old self, is a process. One that God works in His timing. For His glory. If it was an immediate thing, there might be the even WORSE temptation of boasting about it as our own work. For our own glory, and not His.
Jesus compared the lost and the saved to sheep and pigs. Once a man is saved his desires change so that he no longer wishes to do the things he once did - he may fall into the mud but he is not happy there. A pig can be all dolled-up for the county fair but as soon as that clean pig is let loose he’ll find the first mud puddle to wallow in . . . a sheep will bleat it’s head off.
A sheep would not give a speech to a college campus dressed up like Marie Antoinette . . . but a pig would.
Sorry, but that is the facts of the matter.