One of the reasons software gets released in scripts rather than packages is because the root package installation mechanism is root accessible only. Most companies restrict root access and package installation is blocked by proxies. The combination of which means that scripts that can be downloaded separately and run are much easier for enterprise developers to use and get started with.

Until the average enterprise realises that packaging and installation needs to be done better we will always have the need for mechanisms that hack around the problem that system admins cause for the users of the servers.