If the case in favour of asp.net is strong then may be we need to
change the developers? The question is how strong is asp.net's case in
comparison with php?
For all intents and purposes PHP is OK. You can think of it this way:
PHP is best for simple applications (quickier to build, but harder to
maintain). ASP.NET is better for more complex applications (takes
slightly longer to build simple stuff, but ASP.NET has better
maintainability).
When compared to ASP.NET PHP, ASP, CFML, etc all look primative.
PHP does have one advantage - it is multiple platform. If you need your
web applications to run on several OSes, PHP is the way to go. However,
if you're content with Windows, I personally believe ASP.NET is the best
framework to use.
If you can wait, ASP.NET 2.0 is around the corner. 2.0 adds serveral
features that will blow ASP.NET 1.1 out of the water. New features
include a built-in templating system and Client Side Callbacks which
allows a browser to refresh data or to interact with the webserver
without reloading the webpage (works only on IE but you can buy a
similar product for .NET called Dart LiveControls is multi-browser
compatible)!!!