I blame Bill Clinton for repealing the Glass-Seagall Act
Clinton definitely bears some of the blame, but the the repeal of the Glass-Steagall Act was perpetrated by the Gramm–Leach–Bliley Act named after the three Republicans who introduced the bill. The bill passed a Republican majority house and senate and was signed by President Clinton, obviously a Democrat. Blaming only Clinton is definitely looking at an extremely small part of the picture: this was the culmination of Republicans working with Democrats, the legislative branch working with the execute branch, and lobbyists of the private sector working with politicians in the public sector. All of these groups came together to ensure that the banks would be able to repeat the same actions that led to the Great Depression and was guaranteed to fuck over everyone at some point in the future. The results were of no surprise to anyone who read a history textbook and had half of a functioning brain.
if licensee claims ownership of the work in any form
Your clause wouldn't work since it was Epic's parent company that made the ownership claim. You would need to put something nice and broad in there about parent companies, partners, or affiliates. I'm sure a lawyer would know exactly how to close that loophole.
Why is this argument not used against X11?
Because Wayland is being written with a clean, modular design that doesn't attempt to tightly couple a bunch of unrelated nonsense into it to create a complicated mess. Because Wayland is being written primarily by former X developers who have pushed X to its limits but have no choice but to start from the ground up to get modern features such as tear-free drawing. Because Wayland is capable of running X applications thanks to a compatibility layer. I'm sure there are plenty of other reasons that escape me, but these are just a few off of the top of my head.
"The only way for a reporter to look at a politician is down." -- H.L. Mencken