There is this section, which acknowledges the problem of replacing components:

"We also need to consider system reliability. If a dielet is found to be faulty after bonding or fails during operation, it will be very difficult to replace."

Their proposed solution (which is not repair):

"Therefore, SoIFs, especially large ones, need to have fault tolerance built in. Fault tolerance could be implemented at the network level or at the dielet level. At the network level, interdielet routing will need to be able to bypass faulty dielets. At the dielet level, we can consider physical redundancy tricks like using multiple copper pillars for each I/O port."

Your point is still valid, just wanted to call out their their thoughts on the issue.