As a Presentation Layer guy I can tell you that I’m seeing a shift of the types of successful developers out there in the field. Those developers that can bounce around between different API’s and syntaxes are the ones that are in demand and those developers that know one technology or platform well aren’t.
I personally think it’s because of the fragmented nature of our target platforms. Programming for one platform is a luxury most programmers don’t have nowadays. This is why frameworks came to be and are used so heavily. Just abstracting the differences between platforms is enough for most developers to ditch “hand coding” and deal with the integration issues. Look at the popularity of Javascript frameworks like jQuery. Nobody coded in the way jQuery works before jQuery (the whole chaining thing, and anonymous functions), yet now more than 50% of websites (made up number) use jQuery.
To become a successful developer in the next decade, you must be a generalist. It’s a completely different way of thinking. You have to actively try NOT to learn too much of one platform for fear that it’ll bias you against all the other languages you’ll have to work in. For example, coming from more structured languages, seeing the jQuery chaining and use of anonymous functions would turn off most developers and they’d shy away from using it. However, it’s the best tool for the job currently, and not using it based on it’s weird syntax would be a mistake. Same thing applies to MXML, WPF, LINQ, C#’s var, etc and all sorts of new improvements to languages that people don’t use because they’re “different” and give you “less control”.