How worried are we really about surveillance on undersea cables, by China or otherwise? Almost everything over those fibers is already encrypted. Are we worried about metadata? Assuming the hostile power in question already has a bunch of TLS private keys to work with?
Not just the surveillance. The other fear is that an adversary can just shut out countries at a whim.
Of course, it's easier to just change a policy at an endpoint you control, rather than cutting up undersea cables and shooting down satellites.
"Oh, a fishing trawler has cut your country's internet access ? Tzz, tzz, tzz, those sub-par american cables ... No worry, you can buy ours that happens to be much sturdier and at the low, low price of whatever you paid before the cable was cut".
An idea is that nations are storing the encrypted packets now to decrypt them once they have access to a number of sufficiently fast quantum computers (store/harvest now decrypt later). This assumes the data will still be useful in the future.
