I am glad you finally got your install working, although I can't say that I agree with all the conclusions reached. Rarely, should you have to drop the db, and I know of no situation requiring you to delete the website. It is only a few simple tweaks to any website to force a clean install.
If you reach the "Click Here to Access Your Portal" screen without errors then the only problems that could remain are a configuration problem on your site or in the DB, none of which that I have ever encountered require deleting the db or website. If you encounter db related errors during install, then droping/re-creating the db is the easiest way forward. As for the website - there are only a couple files which are "touched" during a standard installation: The web.config and any modules that were installed. Deleting the <add key="InstallationDate" value="3/22/2007"/> line in web.config is generally all that is required (unless you messed up the connection string - which you should be able to test during the installation wizard). This method also requires that you "re-register" the previously installed modules from the module definition screen.
While I can't detail every possible scenario in this post, I can say that you do need an understanding of what is going on during install to know how to resolve installation issues. But the same is true for pretty much any software. If any installer fails, you are often in no-man's land. At least with DNN you can be pretty certain you will never be spelunking through the Registry trying to remove hundreds of application configuration references left over by failed uninstalls (I have been there enough to know that it is not an uncommon requirement for failed install/uninstalls from many major software vendors including Microsoft). Even if you don't personally have the understanding required to recover from a failed install, if you come to the forums with a good attitude and offer the necessary information (note the lack of any specifics in the first post) then someone here is more than willing to help, and yes, if you come here looking to rant without giving people a chance to help then you will often get responses like Alex's. The DNN crowd is a very passionate community and it is hard for many of us to keep quiet when people are taking shots at the software that many people are using every day to successfully run companies both big and small.
Like every piece of software I have used, there is always one more bug to fix, another feature to enhance or new functionality to add. It never ends. We do the best we can with the time we have, our current set of resource and our current set of processes. While we don't really have control over the time issues, we are constantly looking for ways to improve our resource issue, and to improve our processes so that our software continues to get better and better with each release. It was not all that long ago that there were no automated installers, and very little documentation. We are fixing these and a host of other issues with each release.
The one thing that DNN has over many commercial applications is that we have a very active community. No matter how good documentation is for software, it is always just a snapshot of a small group of people's understanding of the software. There are often important pieces of information that don't make it into the documentation (or it is there and buried in 5000 pages of other "stuff") and that is where the community really shines. The community is a giant pool of knowledge about the current state of DNN. Not DNN as it existed 18 months ago when some book was written (note that the words in the book are formed many months before it ever hits the bookstore shelves, so in a fast moving product like DNN, a book is often mildly out of date on the first day it is available for sale), but the state of DNN as it exists today. The lessons learned from hundreds of thousands of installs on every configuration, and in every language imaginable. You will never be able to replicate this in print. So if you have problems - RTM first and then come to the forums to supplement what the docs might have missed.