Jira products Maximum*Confluence Maximum*Overall Maximum*
I don't believe storage limits will change as of today.
On the same note, the storage page you linked has a last update as of 19JUL2018 and Atlassian does a very good job at ensuring their documentation stays updated.
I would suggest for now, vote for this feature request to get more storage:
👋 Hi there, a few of us at Atlassian would love to learn about how you use "space settings" functionality in Confluence. A facelift to the space settings is long overdue and we want to start with im...
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