For disc games, the game needs to go through certification in time to be printed, boxed and distributed. At that point, developers are usually still one to three months from release, which tends to mean you need one and a half to three and a half months to get the game done, and then you still need to keep in mind that unpredictable amount of time you’ll spend in certification.
I've been on quite a number of console titles in my career, and it's never been a number like that between "done" and "release." Many console manufacturers let you pre-certify things a few months before gold to get a basic check of what will need tuning. Additionally, quality publishers will have internal teams to pre-pre-certify your submission and help you fill out the forms, files, and everything else. That's one of the services publishers bring to the table compared to indie -> Console Maker directly.