The WordPress development team is working tirelessly to bring up the auto-update button for their themes and plugins.
This is primarily because the website owners usually install themes and plugins which they forget to update.
WordPress has already released an auto-update feature for the plugins and is currently working on the auto-update for the themes.
Once the auto-update feature is fully released, site owners will be able to update their themes and plugins by checking an option in their website’s admin panel.
Check out the images below for more details on how it will look like after it is fully released: