I'm guessing this was meant to be a troll but really things aren't as bad as you make them out to be these days...
If you're setting up a mail server there are packages available which integrate all of the things you mentioned above into easier to manage / maintain systems. For example one popular one is iRedMail http://www.iredmail.org/features.html
which can be set up by an intermediate user in around 1 Minute [Video: http://www.youtube.com/watch?v=wi8CF3RKRm4%5D
If you are implying it's much more complicated for the end user then you're kidding yourself as well. These days there are guides for most popular distributions and usually it's not much more difficult than installing the software and/or configuring an addon. For example, the Ubuntu community guide has easy to follow instructions for configuring Thunderbird with ClamAV. The process is by no means difficut (install, set ports, install addon) and takes less than a minute to complete for a novice user capable of following some instructions.
There are of course users who would find following such a guide too difficult but really these users simply lack the experience, confidence, patience or time to do so anway. They're likely the same users who pay somebody else (or come to you, their friend / relative) to install the software for them
Point I'm trying to make for people thinking of giving it a try is that it is a lot easier to do than the parent implies - even for novice-intermediate users.