[archangel_one]

Sounds to me like it comes with a raft of legal and practical troubles. Say company A has licensed a copy of this software and made some modifications. They cannot publish these modifications for general consumption (eg. on Github or similar), so it's not really obvious how anyone will ever know they have this potentially useful code. If some other company B somehow did find out that they did have it and come to A asking for them to share their code, A don't know that they're legally allowed to give it to B because they aren't the licensor.

Also, I disagree with your stance that the GPL "entirely upends" the possibility of making money off licensing software. Trolltech were (until they were bought by Nokia) an example to the contrary; Qt was dual-licensed under the QPL and GPL for years and they were obviously making money out of all the companies that didn't want to have to GPL their product.

Finally, it's not really clear to me that anyone really wants this model; there are companies (like iD) who are keen to open source at least some of their software. Many other companies are not interested in releasing any at all. It's not at all obvious to me that there is some sort of middle ground of companies who want to release their changes but only to other companies who have licensed the same software, thus forgoing the whole feel-good factor of open source, arguably much of the point of it and certainly the entire Free Software angle.