There is no conspiracy I assure you! :)
As a Plugin developer for the last 3yrs or so I can answer some of your queries for you, as well as my own take on it:
- Plugin devs have NO arrangement, or even any contact with Automattic whatsoever.
- Plugins developers have no control over the approval or rejection of their Plugins. We get access to upload new versions but that's it!
- There are not a huge amount of Plugins trying to sell a pro version, maybe I am wrong here, but most just happily give away the full Plugin version completely for free!
- Plugin developers work pretty much for NOTHING and get precious little feedback or thanks from users (there are millions of people relying on our Plugins everyday).
- We continue to write them as most of us enjoy a challenge and love WordPress and the community surrounding it.
So, have a heart, all Plugins on the repository are the result of someone's hard work that they (to reiterate) are giving away for free! If they have a super duper version that includes top notch, fast turn around, support plus a few extra goodies thrown in for good measure then they should be allowed to do it (within reason) from their 'lite' versions on the repo.
Have you ever coded up a Plugin? Maintained it? Written documentation for it? Regularly update it when bugs are found? Added new features? Took time out to answer support questions? And not had a penny in return? Well, I can tell you that the downside of writing Plugins is that it can be a pretty thankless job being a Plugin developer, and your comments don't inspire me to do continue to write them that's for sure!
Theme developers are allowed to have a commercial entry on the WordPress.org site for their premium themes, so may I ask what is so wrong in a Plugin developer trying to make a little income from doing what they love - coding for WordPress, by providing a pro version of their Plugin!
Who loves Plugin developers, come on, put your hands up?