I don't think Ajax and Struts can be compared because Struts is server based, and Ajax is client based. As one of the articles you referenced said...
Developers are getting used to the old way of doing things and are basically copy and pasting code from one application to the next.
To your second question. If you say, yes Dynamic HTML is the way to go then you need to follow through on the argument and say Java and C# are not the languages to use when coding Dynamic HTML.
The productivity you have with either Ajax or Flex is very hard to achieve using a traditional GUI programming language.
There is a bigger issue here in my opinion. I feel that writing GUI's using technologies like Java or C# is passe