User blog comment:Ducksoup/The Future of Infoboxes on Wikia/@comment-5590118-20150825212321/@comment-24473195-20150825222950

"This helps to separate the different views so that they can be used when they are appropriate and on the page you still use Template:NavBox."

Unfortunately, the vast majority of wikia/wiki users are non-techies. Even if such an extension were enabled chances are that a miniscule percentage of wikias would use them. As an example, it was quite surprising that staff openly acknowledged that only 4% of wikias actually use custom javascript. Perhaps less than half of those use "complex" and rare parserfunctions and in  some cases most contributors don't know or use them.

So deploying a solution like that would mean that only a small percentage of wikias will benefit. With something like portable infoboxes even non-techies managed to convert franken-templates into potboxes, and in cases where they failed they could get quick help in the forums, while with an extension like that chances are that most wikis would simply ignore its existence, as they ignore (or are unaware) the existence of custom javascript.

In any case, such an extension exists, see. You could always ask staff to review it and enable it if it is stable enough.