Why do smart objects rasterize vector content?

If a vector object is brought in from Illustrator, it becomes a "vector smart object" and you can resize it until your heart's content and it remains a vector object.

Vector Smart Objects still output as pixel data.

If I get a request to change that text, i want to change the text inside one single smart object so it update in all artboards where that smart object is being used.  This all works now, except my text is not sharp because it has become resized.

You can upsample the SO then.

Photoshop renders pixels for smart object Layer object to be used as the layer contents. These pixels are locked and can not be changed by Photoshop tools and features.  These pixels are use as input for render the layers composite..  These pixels will be filtered by smart filters  you added to the layer and constrain by  any filter mask you added these will also be interpolate by the Smart Object layers associated Transform and then blended into the documents composite.  Smart Object layers behave like raster layer except for vector smart objects which are Placed AI files these are resized via vector graphic. 

So if your layer object is a Photoshop object that has vector layers if you want to work on the vector layers. You need to open the layers object into Photoshop by double clicking on the smart object in the layers palette.  Photoshop will create a temp work File for the object in your user ID temp space. Then the work File will be open into Photoshop for you to work on.  You can edit your Vector layer and save the temp Work document. When you commit your changes Photoshop will use the your updated temp work file you saved to update the smart object layers object and render a new set of pixels to use as the layers content.

Your best option would be to create an asset to the Creative Cloud and bring that into your multiple documents. Then if you edit it, you can update each document. Unfortunately, that is just the way the smart object works and you can't have the vector smart object in two documents.