This is why I'm so happy about the California top-two primaries - they've created competitive elections in a dominant-party state. But they were only created through a ballot initiative over the objections of the legislature.
The U.S. is one of the older representative democracies now with the oldest written constitution, which is also difficult to change. Making elections more modern, fair, and actually representative will take a lot of effort by citizens.
If SCOTUS finds in favor of existing extreme gerrymandering practices in the Gill v Whitford case, it will be necessary for citizens to actively crack the grip of the two incumbent political parties, or accept generation long single party rule disconnected from representation of the citizenry. Gill v Whitford is the easier path, but modern elections still need to be a goal: city, state and federal. It will take time.
Have they really? It seems more like they've pulled candidates towards the center slightly and relegated third parties to the sidelines even more.
When the initiative was passed, third parties opposed it because they said it would make it more difficult for them to run competitive or even influential (but unsuccessful) campaigns.
For statewide races, the jungle primary approach seems to come down to which two Democrats attract enough votes away from other parties (and other Democrats) in order to make it to the final two.
http://latimesblogs.latimes.com/california-politics/2012/11/...
Same with Republicans in liberal districts; a choice between two Democrats is just what the voter profile of those districts leads to, and at least this way the minority party gets to influence the final winner.