Installing Symfony can be done in many different ways but since Symfony 2.1, the preferred way is through Composer. So, it's time to deprecate the Symfony PEAR channel.
According to the website statistics, the Symfony PEAR channel is mainly used to install PHPUnit dependencies and Sebastian Bergmann announced the end of PEAR support for PHPUnit recently. Also probably because installing Symfony via PEAR is not even mentioned in the official documentation.
As of today, we won't publish PEAR packages for Symfony and Symfony components anymore. The current Symfony PEAR channel website will continue to work and serve current versions of the various packages hosted there, but it won't get any new versions. Note that I don't expect to close the website anytime soon, so it should work for the foreseeable future.
You can read more information about this topic on my personal blog.