I'm not really sure what JR is talking about, or what kind of axe he has to grind, but real web companies and professional designers and programmers DO use Dreamweaver.
JR's little rant about market strategy and beta testing and such is, well, at best, unfocused, and not really relevant to the question. What JR is going off about is the PROCESS of project planning for a web design project. Of course you have do all those things, duh! But any large shop, that makes large, substantial sites is going to break all that down into a number of different steps (completed by a number of different people). Where Dreamweaver comes in is at the programming and development phase; everywhere else it's not really relevant.
Imagine for a second that the question was about auto makers and whether or not professional manufacturers used wrenches. JR's answer (extrapolated to this new question) would seem to indicate that professional automakers could not use wrenches because auto design involved steps such as market research, concept creation, design drawings, prototype creation, real-world driving and safety tests, advertising and distribution to the dealer. Since a wench can't do all of that, professionals would never use a wrench! For shame!
I'm not saying Dreamweaver is the best tool for the job, but it certainly is adequate, and has nice synergy with the rest of the Adobe suite. And many professional shops do use it (some quite large). So why spend additional money on another IDE when a good one is already packaged with CS (or CC now)?
I used to work at the largest Marketing / Design firm here in the Central Valley and we were an Adobe shop, and used Dreamweaver. We designed and coded many very large sites for major utility companies, hospitals and governments, all on Dreamweaver.
And as a real professional, I can tell you that using any sort of IDE (Dreamweaver or otherwise) will speed up your development cycle. Notepad ++, while a nice text editor, is not an IDE. If you're a freelancer using Notepad ++, and billing hourly, STOP! You're doing a major disservice to your clients.
Dreamweaver's got a lot going for it:
Code hinting
Code completion
Built in references / KB
Balance Braces / Brackets / Parentheses
Tabbed files
Tabbed subfiles
Dynamically located subfiles
Customizable Snippets
Save directly to server via FTP
Integrate with version control
Great site management
Like any tool, you gotta learn how to use it. Many people hate Dreamweaver because they don't understand how to get the most from it. It has a lot of moving parts that can do many powerful things that do have the potential for abuse and misuse. It's very much like the novice photographer with new high tech camera wondering why their pictures suck, or a untrained carpenter with a new power saw wondering why his cuts don't line up.
Is Dreamweaver my favorite IDE? No, there are many choices out there with more features, but Dreamweaver it still quite good. If it's what you like, or what you got, use it! Don't let the haters deter you.