Any user can make personal channel(s) on YouTube. Most often it is seen that channels are merely made to reserve particular channel names and there are no contents in those channels. Let’s see in the following acticle, what happens to those channels?
In this way several good channel names have already been created without any content for long time. Most often spammers make channel names impersonating popular brands.
What happens to inactive or duplicate YouTube channels?
In general, YouTube does not delete any channel even if it is inactive for long time. However they may change this behaviour in future, it is upto them.
But for duplicate accounts, it is seen that YouTube deletes channels which infringe a popular brand. If you are the owner or copyright holder of a brand and there is duplicate channel with your brand name that you didn’t authorize, then you may ask YouTube to delete such fake account with proper proof of your ownership.