Presumably they're planning on doing in-orbit propellant transfer to reboost the satellites so that they don't have to let their GPUs crash into the ocean...
Hell, you're going to lose some fraction of chips to entropy every year. What if you could process those into reaction mass?
These are all things which add weight, complexity and cost.
Propellant transfer to an orbital Starship hasn't even been done yet and that's completely vital to it's intended missions.
Ionizing radiation disrupts the crystalline structure of the semiconductor and makes performance worse over time.
High energy protons randomly flip bits, can cause latchup, single event gate rupture, destroy hardware immediately, etc.
Just shoot it into space where it's all inaccessible and will burn out within 5 years, forcing a continuous replacement scheme and steady contracts with Nvidia and the like to deliver the next generation at the exact same scale, forever
The physics of consuming bits of old chip in an inefficient plasma thruster probably work, as do the crawling robots and crushers needed for orbital disassembly, but we're a few years away yet. And whilst on orbit chip replacement is much more mass efficient than replacing the whole spacecraft, radiators and all, it's also a nontrivial undertaking