The key doesn't have to in memory on all of their front end servers. Any respectable company that cares about security wouldn't put their TLS private key on all

The key doesn't have to in memory on all of their front end servers. Any respectable company that cares about security wouldn't put their TLS private key on all of their front end servers anyways. You expose a special crypto oracle that your front end servers talk to; the oracle can be a specially hardened process on a dedicated server or better yet a HSM; the point is, the private key is never in memory on any server that handles untrusted data.