If this hypothetical company wanted a person who understood HTML, PHP, AJAX, etc, then why would they hire a Dreamweaver guy? Why would the Dreamweaver guy be applying for a non-Dreamweaver position?
You are correct that pinning your career to a particular technology isn't a good idea. However, you don't seem to understand that big corporations don't hire computer scientists (programmers) and then have them learn the products that are being used. They typically want to hire someone who already has experience with what they're using.