Genres tend to be backward looking.
In other words, new genres tend to be derivative. Influenced by a previous genre. Very hard to avoid, not meant in a bad way. Many times, some influence comes from a major label executive or producer so that the new style has some mass appeal.
Not what I was saying, though it MAY be the case, but not necessarily. I only meant that they are named AFTER they exist, not before. It's not like somebody said one day "I'm going to invent a new genre and it's going to be called Rock n Roll".
Lots of new genres do have roots in previous music, but that doesn't mean it isn't a new genre just because you can trace its roots back to something else.
My point is just that something here or there that might currently just seem derivative of other stuff may not yet qualify as a genre, but as specific properties build momentum among multiple artists, 10 years from now we may look back on the 2010's and identify music as [insert new genre] even though we haven't invented that name, or classify it that way now.
Maybe it's just that we've all gotten to an age where anything we hear, we just blow off as already been done rather than consider it something new. I mean any of the electronic music over the decades, if it didn't resonate with you, could be blown off as "well Kraftwerk was already doing that in the 70s", so it doesn't count.
Honestly, though, I think genres have more historically been created by Radio Stations to target a specific market. Whether the programming is Modern Rock, Rock, or Classic Rock, when it boils down to it, really is determined by the target age demographic, nothing else. So probably our means of consuming music in the modern age has as much to do with it as anything.