I wonder how long it will be before someone who really valued the plugin ends up creating a fork, minus the marketing stuff and submits that to the repository as a replacement

It won't take much time to create a fork removing the the optin form. The question is the guy who will release the fork can continue to support the plugin? It might work today but what about the future?

I have spent a couple of years full time in this maxblogpress project. I know it takes a lot of work to support a plugin. Wordpress evolves and old plugins no longer works. We have released numerous updates to our plugins and gave support to thousands of our users. Can the guy who release the fork can dedicate their time to support it? That's the question. May be releasing a fork means making the plugin die for forever.