"vertical-align" has always been around since the beginning if you're okay with setting the line height to the height of the page.
The original model for style might have been text, but that didn't stop anyone from doing what they needed. The question has always been more whether you really want an element vertically centered to the page rather than to a page section.
https://www.w3.org/TR/REC-CSS1/#vertical-align
"vertical-align" has always been around since the beginning if you're okay with setting the line height to the height of the page.
The original model for style might have been text, but that didn't stop anyone from doing what they needed. The question has always been more whether you really want an element vertically centered to the page rather than to a page section.