Rails is now pretty old (in tech years) and one reason for active participation and contribution to the community is that the Rails team continues promote forward movement in the framework. So Rails is also always new.

A lot of the stuff people moan about (e.g. lack of backwards compatibility and constant breaking changes) is also what keeps it fresh. It's not hard to introduce new best practices because the old ones are continually tossed out. This can't be said for a lot of open source projects that value stability over change. (For some projects, stability is rightfully more important).