It's my impression that the feature was dropped b/c it didn't solve the underlying problem with gem versioning/distribution. Github got behind gemcutter early

It's my impression that the feature was dropped b/c it didn't solve the underlying problem with gem versioning/distribution. Github got behind gemcutter early and urged everyone to make the switch. In the rare case when you want to install a gem version of an obscure fork, you can just install it as a submodule instead.