There is absolutely a positive correlation between ease of installation and the quality of a product. Between cost and quality too. Software without an installer is incomplete and unlikely to be able to compete with traditional commercial software. If it tries, it's likely to come out the loser. Despite how long emacs has been around, there's also a positive correlation between the existence of an installer and the extent of a products evolution/version, and despite what others have said about my preference for higher versions of software (and modules), the higher, the better.
Site all the exceptions you want. My common sense and experience tell me I'm correct.