A "House of Cards" is a wonderful English phrase that it seems is now primarily associated with a Netflix political drama. However, its original meaning is of a system that is fundamentally unstable. It's also the term Sarah Thiele, originally a Ph.D. student at the University of British Columbia, and now at Princeton, and her co-authors used to describe our current satellite mega-constellation system in a new paper available in pre-print on arXiv.
You understand that not all satellites are in Low Earth Orbit right? And even those that are in LEO, not all of them are in the same orbital path. So even if all of Starlink satellites exploded and polluted their orbit with a worse case scenario, GPS wouldn’t be affected (GPS orbit is 20,000km away from Starlinks with hugely different Delta V required to interact with them). LEO Polar Orbits wouldn’t be affected, and any space faring nation would still be able to launch missions that avoid the polluted orbital area.
Kessler syndrome is a concern for “economical” space exploitation, but not actually an issue for a Government that cared and wanted to prevent it.
I’m aware that not all objects are on the same hight, there are several layers, but currently all layers are saturated with sats, working or not and thousends of tons of debris of every kind. This is getting worst with every launch of new sats. In the page i posted you can see the current objects and their data in real time. Every possible crash, like the some month ago, the small object perforanting the Chinese space station, luckily with not big consequences, and similar which even destroyed some sats, augmented the amount of trash. A lot of abandoned sats out of control, like the one from Rusia make the situation not better. Also not a huge amount of sats not able to changing course to avoid a crash.
You cannot fill the sky with all kinds of objects ad infinitum, hoping that this will not have serious consequences in the long run, and we are already about to reach this limit. I don’t care about spy or large corporate satellites, starlink etc. but if they are destroyed they produce thousands of tons of garbage that further endangers essential satellites (GPS, Communications, Climate…) even more, avoiding any new launch , when the expression “launch window” takes on a literal meaning, making it a Frogger game.
Here an report from the ESA, maybe more convincing as my post
https://www.sdo.esoc.esa.int/environment_report/Space_Environment_Report_latest.pdf