#Wikipedia, an article never finds its final form. There is no final form, there is always a potential next iteration, never mind the quality of the current version. The same is true for Wiktionary; there is always room for another translation, another attribute.
When you want final forms, you produce something static. There are many reasons why this is done. One reason is to create a final version and create a collection of articles and calling it a book. Such books can be priced and it is quite legitimate to sell them on ebay. This has been done and when another such publication is found there are usually some people who complain about it.
For Wikisource and Wikibooks however there are finished products. In Wikisource a project can be considered finished once the proof reading of a digital text has been completed of what started as a scanned text. Only when it is finished, it is ready for easy public consumption.
What Wikisource does is provide the tools for this process. Essentially Wikisource serves a community that is engaged in a workflow. What it does not do so well is publish the finished products and find an audience for them.
The work at Wikisource is important. Its finished products are relevant and they are worthwhile. They fit in our aim to share in the sum of all knowledge. We can give things away, we can ask for a contribution but we owe it to our public that we make a best effort in making all this knowledge we are the custodian of easily accessible.
We may need a new project .. "Wikipublish" where we publish final versions of our "Wikisources". Where we publish collections of Wikipedia articles. Where we publish our "Wikibooks". We do not need much marketing, we need to make our finished goods available to a public and provide it in a format that it finds easy to digest.