> The ecosystem would be greatly improved if someone made a great (probably rust based) in-memory low level pdf reading and writing data structure.

> Not sure what would economically cause this to happen, but it would be great.

Writing a library that is better than all the others is difficult to begin with. Continuing to upgrade and maintain it and fix bugs is even more difficult. Even with the right funding, you'd have to find someone who wants to keep at it year after year. When they inevitably lose interest, you'd have to find somebody else to take the reins--and weather the storm of complaints during the down time.

In short, thank you for volunteering to write and maintain this library for the rest of your life! :)