Assuming an application is an application .....
"developers should look at web, mobile and cross-platform "
That rather depends on what you're developing. Not everything is an office application, or a domestic one. We do multi-PC networked control systems. They can't be web (though they are networked). They don't make much sense mobile. In many ways they are more like hardware than software.
But we do include desktop applications, with GUIs. At the moment they may be Qt, or WIN32.