Comment by joshmoz

This is not an attempt to reduce the CA system to a single CA. The intent here is to provide a simple and free way for anyone to get basic DV certs. If we can also contribute to CA best practices, and help improve the CA system in general, we'd like to do that too.

Let's Encrypt is only planning to issue DV certificates, since that is the only type that can be issued in a fully automated way. Many organizations will want something other than DV, and they'll have to get such certs from other CAs.

Also, our software and protocols are open so that other CAs can make use of them.