I was just wondering will this badge stay forever or if I get surpassed by people will this badge be demoted back down to silver or will it stay as gold.The latter. You can get surpassed by other people who have contributed more than you. Also, it is possible that contribution you have made get deleted, this will also impact your score.
For more information about the badges: https://www.imdb.com/badge/
Other than the member’s Tenure Badge—as Marco said—all other badges (or mostly all) are susceptible to change since they determine one’s total live contributions.
To see this for yourself, if you have acquired, say, the 2019 Oscar Highlights Badge, you could pick a title, and reset your rating to zero.
After a while, you’ll notice that the badge has vanished into thin air. Don’t worry, it will return to its rightful owner once you recast your vote.
In this world, nothing is forever.