Is the notion of specific genres beginning to blur at the edges? For example, crime writing seems to offer so many possibilities these days and a number of books I've read lately seem to build on a mix of at least two kinds.
Readers appear to be divided on this. Some relish the cross genre plots( scifi and crime provide a particulary interesting combination), while others are more than a little upset if the book they have chosen doesn't keep to the advertised genre.
Yet in the end all novels deal with human emotions: no one life is curtailed by a single set of actions. Criminals and spies can have romance, lovers can be involved in crime (even murder), historical novels provide a fertile ground for crime, passion and intrigue at the highest levels and even in the future surely the human race will continue to suffer and enjoy the same passions as we do.
Perhaps there is an issue about the balance in novels. In a crime novel, readers don't want the bulk of the action to focus on romance: in romance readers won't be happy if the lovers seldom meet because the hero spends most of the time pursuing criminals.
I write cosy (or, as it's called in the U.S., cozy) crime set on the island of Bute where the emphasis is on the mystery and have learned it's very important readers of crime novels know what to expect. There's an excellent description on the website of an American blogger, Danna, (www.Cozy-Mystery.com) and I've found the guidance there a great help.
As a reader I find the huge choice available to be one of the best aspects of the 'publishing revolution.'
In the end it probably all comes down to a good story and engaging characters, no matter what the genre!