If they are already deploying it (according to the linked article from September), then they've already been at it.
But here's the thing: you don't put desktop machines on the network to do encryption, you build RSA cert verification, DHE key exchange, and AES crypto in a stand-alone chip, and you put that chip in your network hardware. Then you're not pulling it off the network, you are building into your switches and routers, which are already processing and routing traffic based on ARP MAC tables. All of your data is already chopped into frames in the router/switch, passed into buffers for routing/switching, then distributed to the proper ports.
You need a nice pre-designed and manufactured AES coprocessor with support for CTR mode (the AES mode for WPA2 does CTR encryption and CBC for content verification, and both TI and Amtel have a chip for this), then even if you can't go fast enough with one, you can go parallel with as many as you need.
Or if you are doing it yourself, you build some test hardware with FPGAs for dozens of iterations a day, then use your results from that to fab an asic.
Don't get me wrong, I'm not saying that it is trivial. But the cost delta (after design and tooling) between a router/switch that does encryption vs. one that doesn't isn't an order of magnitude, it's closer to $5/gigabit or better (the Amtel chip is about 65 cents each in volumes over 4000).