Rightwing extremists are simply going to have to accept the fact that they're a minority in the GOP – a loud, intimidating minority – but a minority nonetheless; and rightwing extremists are also going to have to consider the possibility that starting next year their failed, extreme agenda will be ignored by the GOP mainstream, more interested in responsible governance and retaining control of Congress come 2017 than appeasing the TPM and others on the radical right.
This weekend's budget agreement is likely just the beginning where irresponsible extremists such as Ted Cruz will continue to be frustrated by a GOP establishment focused on retaining political power and influence, not preserving the purity of rightist dogma venerated by the TPM.
Don't know if you noticed, but more and more Conservative 'extremists' are winning elections. So much that the clowns in charge of GOP are bypassing their base and funding people to run against these people. These clowns have been going against the GOP base for some time. Sooner or later revolt will happen.
You just committed an electoral error that is common, namely, the easy desire to compare mid-term election results to general election predictions. There is an entirely different "clientele" that shows up for presidential elections, and millions, millions, millions more go to vote.
After the 2010 midterms, the Right was crowing that Obama was cooked. He won re-election two years later.
It's not the extremes that hold this great Union of ours together: it's the middle.