Wow, this is a fascinating answer. I really like your thought experiment with LibreOffice. Imagine something even more nefarious: The whole LibreOffice team "quits" to start a company that does exactly the above. After building a large user base on their web-only version, they begin to charge for premium features. All while never distributing the GPL code ever again. To be clear to all readers: This is only a thought experiment!

Further: If we think about cloud-based AGPL apps: For the most part we are talking about web-apps, which, in most cases, will always include JavaScript running on the user's host. Does FSF or AGPL have anything to say about this source? I ask because I am thinking deeper about your idea: What if the not-so-LibreOffice was nothing more than compiled into WASM (WebAssembly) and run in your browser... so the "server" (SaaS) was doing nothing except serving a huge binary that you run locally in your JavaScript VM. Plus, the compile from C/C++ into WASM could reasonably obfuscate the original source. I do imagine a future where lots of commercial apps are nothing more than C/C++ compiled into WASM then run through a browser. This would provide some source code privacy (that vanilla JavaScript cannot provide today) and reduce the burden of installation issues.