@Devin Walker - agreed.

I think things are improving as plugin and theme authors are becoming more aware of security considerations, however, some of the less profitable ones will simply not spend the time to update their code.

Of course, none of the efforts to inform theme & plugin authors to get them to update will count for anything if there are still lots of businesses who don't value regular maintenance on their websites (whether by themselves or a third-party). There needs to be equal effort spent in this direction too.

So, battle is really on two fronts whenever vulnerabilities such as this are discovered:
1). Getting theme and plugin authors to update their code
2). Then communicating to businesses and web admins to help them see the value in keeping their websites up to date.