I actually think its a good thing. It allows those of us that are developers (full or pt) to do things that has been asked of us for so long.
The extra functionality and added usability (when used correctly) makes for better sites and better interaction for users.
Of course, AJAX become a star, it's because of google.
So I don't think AJAX is a signal of unhealthy, just because some webmasters use AJAX to show off themselves only.
And I think AJAX is good! Very Good!
ajax will be a a great affect on CPM rates.
The great thing about AJAX is that you can create Flash/Java-like effects in >95% of available browsers without requiring the user to download any browser add-on. It goes without saying that if AJAX wasn't that widely supported then there wouldn't be any hype about it nor would Google use it. In fact, there's a much higher probability that the basic CSS layout of a web page would malfunction than that it would happen to AJAX sections of the same web page...
I think it is unhealthy if you are obsessed with it and lose sight of more important UI/content/marketing factors in making money online.
Of course, like anything else AJAX can be over-used, but it's the web designer's fault not the technology's. IMO web pages over-using CSS stylesheet effects is a much bigger 'problem' than web pages over-using AJAX...
I have to say I lament the demise of frames.
Probably 80% of what AJAX is being used for could be satisfied in a much more simple fashion using frames.
I think where we went wrong was the silly squabble over Iframes. Iframes (introduced by Microsoft) were not an "official" part of any web standard until HTML 4.0. For some reason, they are still thought-of as improper HTML. Iframes addressed most of the clunkiness issues with frames.
Unfortunately, Iframes are NOT an official part of XHTML! (Although browsers still support them.)
What we needed (and still need) is a more-flexible implementation of Iframe. It seems to me that <div> and <span> could meet that need nicely.
Substitute AJAX-like for AJAX above.
To the end-user it would offer the same experience, though, for those use cases which involve simply updating a block of text from the server when the user presses a button.
I agree that iframes are often overlooked.
I'm working on a project right now where I had to decide between ajax and iframes. Iframes did everything I wanted (so far at least) in a few lines of code, as opposed to what would have been some bloated ajax js overhead.