I will try to explain why most should use PHP for a DHTML application. Lets say you are a tech lead, and the gig is to write one of:
1. CMS Portal
As a good tech lead you think effective and are not religious about tech stack; you want to maximise "Return of Sofware" (a good book to read). This means you like cheap operating costs and lowest possible development cost and low risk.
And you Google on serveral open source projects in:
A. You find that there are many 1-5 projects in platform A.(the link I gave). Each of the projects is 80-90% of what you need. So you think... I can save 80% and reduce risk! Cool!
Then you see that some of the projects have 1,000's of customers in production(ex: Drupal) Cool; low risk in proudction track record. You surf some of the client using proucts in the category. They are listed for PHP. 1,000's per application.
B and C. You find... a few applications on those platforms. Likely you will have to develop from scratch. Few reference sites that you can surf. (I know, I wrote a portal in Struts and installed at clients).
You have to develop and you know that accorindg to this: http://www.standishgroup.com/sample_research/chaos_1994_1.php
most proejcts fail. So you want your organization to be profitalbe and not risk a career on a dizaster and have to sue the vendors.
You HAVE to select LAMP!
Yes, if this was the 90's and we started even w/PHP (and we did not do PetStore and EJB and.... etc. ) maybe you can argue that PHP does not have an arcitectualr or tech stack or methodolody advantage.
But as a scientific person, you can just look at the #'s. How many proudction application per each PHP open source project there are (there are a dozen buletin boards).
So you just chose A and deploy day one. Then you spend a few weeks with to add 10-20% missing and you leverage people that did other proudction sucess proejcts in the product you chose.
OVER, the fat lady sang taps.
Look at any J2EE project home page and they are using PHP in fourms, maybe in front page. Sandra, Spring, etc.
The score is something like 10,000 production sites for A and 30 for B+C.
This means that we should be learning from them.
What ever their aproach is... they are more eficent. Darwin rules, thank god for that.
You could write something from scratch in JSP, it be a waste of money, the business is looking for solutions and applications. Else they will ofshore you. (Did you read Haravrd Businees Review article "IT ivesment offers no Advantage"? If somone missed it, google and read it. And cry.
A good arcitect delivers a track record; a bad one.. talks a lot. Yes, you do PetStore + EJB + ORM + JSF + Generators + XP(no requirements) and then you draw a UML and .. right, no thanks. Yah, PetStore. Doing technlogy for technlogy sake is... masturbation. PHP guys are scoring w/ chicks! Look how many pregnant!!!! Even the clients are asking for PHP.
Game over, thanks for playing, we LOST!
I switched to where we (Java) have an advantage on PHP and VB/C# and Flex/Laszlo; that is JNLP+JDNC. But feel free to try to wake up Frankenstin, he is dead.