It's not. It's just that all this work was done for the N97 before you ever saw it, so that it looked easy.

Yes, Nokia could have done this all off-camera for the N900 as well, but they didn't. There have been many threads discussing why, but it all boils down to the old triangle: time, resources, and functionality.

There's also the fact that adding more resources to a project to get one aspect done may slow down the project overall. This is a well-known phenomenon, best discussed in a classic of the software industry called The Mythical Man Month. See http://en.wikipedia.org/wiki/The_Mythical_Man-Month, and the book is well worth reading.