they will remain on your disc until you delete them. cryptic cant unistall what is on your computer, they can only limit access by taking away the 'start button'. you can delete it yourself at any time if you wish.
if they ever bring it back the bulk of it will just copy over from holodeck or tribble rather then be re-downloaded. if you are happy to leave it on your computer then it will do no harm other than take up space.