The Tea Party really just accelerated a wave of retirements of old hands, either against their will or for their "principled" stances. And young Congresscritters, as can be seen with a few of our latest newbies, aren't yet ensconced in all the rule mandated performative behavior.
Ted Cruz, for example, is not crazy in his positions compared to his successor Kay Bailey Hutchison. He's just a way different personality that's epic abrasive. And she had 40 years of experience in electoral politics. He has like seven.
In fact, Hutchinson was more "moderate" when she entered in the Senate in 1993. She was pro-choice, she was more favorable to immigration, did that common split with against gay marriage but for lesser forms of partnerships along with hate crimes legislation, wanted tax cuts that "were paid for", etc. But she moved more and more to conservatism as she stayed to where she left office as a top pro-lifer, against the DREAM Act, against even domestic partnerships, all tax cuts are good, etc. All her late term "moderation" came from the image of her being a long serving Senator who moved up in seniority, etc. She dropped a ton of that Senate language when she ran for Governor.
The Tea Party still wanted to get rid of her, and Cruz was her replacement in part because of that, but voting wise, I don't think Cruz is some kind of major downgrade from Hutchinson. For every area she might be slightly better, you can probably find as many instances where Cruz is at least mouthing skepticism of foreign policy/NSA/etc. whereas Hutchinson was a top Bush War on Terror supporter in every way. So even with one of the worst Republican Senators it's not like there was a sea change in the seat other than rhetorically Cruz doesn't care being an asshole.