My experiences with web-frameworks was that they are relative "unstable". Not that they crash but that there are quite a few changes which then force one to reprogram ones code. I wonder what web development packages you've used and how much work it was/is to maintain that code?
"Changes are a part of the requirement."
I dont think that the web packages that we design changes a lot. If it changes, then it is a bad design. If we use external API's, a very few get deprecated, otherwise most of them are the same.
Some packages used as a JAVA/J2EE programmer: - MVC - Struts - few AJAX frameworks
These are very basic one used. Most the other ones are self developed and once the design of the web package is done, we don't change the design.