I don't think Texas becoming a battleground state is so much a testament to the GOP's demise rather a testament to the changing dynamics of the State in terms of the increasing Latino community. We'll see what happens after Trump, yet I would be very surprised if one election leads to a new party, as we're already seeing GOP leaders start to split with Trump as they're reading the polls (e.g.: Latest stimulus negotiations and now the bizarre election delay call).
New party systems don’t mean replacement of parties but just very different coalitions and policy goals .
If you define it that way, I think there may have been more than 6 systems then...
Not really these party systems are defined like that
https://en.m.wikipedia.org/wiki/Party_system
Look At the US part
Arguably you could add the rise of the Tea Party to that and then more recently, the alt-Right/Trumpers...
