As a general comment... it's pretty funny that this wouldn't be an issue, since they complied with the GPL as they were required to do, and published their sources.
Only the politics of Open Source is such that the projects that they published the changes for were not updated to include the changes, because they felt that it was not their responsibility to update their projects to include someone else's changes to their projects. They felt, instead, that it was the responsibility of the people making the changes to join their projects, and then make the changes with the editorial oversight of the community.
This is somewhat ironic, since they wouldn't have published the sources in the first place, if it hadn't been for the license.
So it's interesting to me that you can more or less not comply with the license by complying with it, and that the license is only effective for however long your product and company are around, and, if not picked up by the community to be carried forward, get lost after a short period of time, even if the company continues to exist.
I guess I wonder if it's legal to sell remaindered product (or used product) without offering the sources, per the terms of the license, or if, after that period of time, the products become illegal to transfer the binary licenses, since the originators are no longer around, and you cant appeal to them in order to get around your personal obligation, as the seller/reseller, to make the sources available any more (but you, as the middleman, failed to take advantage of the offer while it was possible to do so).
Probably, projects need to be a little less pissy about integrating third party changes, fixes, and extensions back into their main line.