Ask yourself, do you want to learn a new way of driving, get your license again and loose all the experience you had? As for newcomers, what if they had to learn both joystick driving and steering wheel driving? Well, I think it’s the same with RSS and Echo. Echo’s wiki says,
“Now, if you want to build a weblog tool, you need to know a variety of different formats and protocols: HTTP, XML-RPC, RSS 0.9, RSS 0.91, RSS 0.92, RSS 1.0, RSS 2.0, the Blogger API, the MetaWeblog API, the new Blogger API, etc. We’d like to make this just one format (Echo) and one protocol (HTTP).”
The final result will be, there will be even more protocols, HTTP, XML-RPC, RSS 0.9, RSS 0.91, RSS 0.92, RSS 1.0, RSS 2.0, the Blogger API, the MetaWeblog api AND Echo. Building on what already exists is evolution, the other way is demolition. This is the same problem with some flash interfaces, innovation is given more importance than backword compatibility.