After more than 5 years of opening some huge part of Delphi code base, just my two cents.
Free software means free as a bird.
In practice, most Open Source "consumers" focus on free as a free
This is a reality, especially for "niche" projects like developing libraries for Delphi.
Here are some thoughts from my little experiment with mORMot.
If you ask what Open Source for libraries mean, it may help you!