Firstly, there is no establishment candidate yet. The vast majority of the establishment (Govs, Reps and Senators) have yet to endorse and a lot of establishment money is still waiting things out to see how things shake up.
Also we have yet to see a big establishment backed anti-Trump TV campaign. There has been talk of one, but even Jeb's big Super PAC hasn't started going after Trump (they are focusing on pro-Bush ads). Back in 2012 the establishment piled on Gingrich before IA with big spends and took him down, when he popped back up again by winning SC they did it again in FL and took him down again.
As for how 'Trump will always win' the money game, as I noted in the fundraising thread, Trump has yet to really spend any money. He keeps saying he will but he hasn't yet. If the establishment (via Rove and/or other outside groups) spend $50M taking down Trump will he match them or outspend them? I'm not so sure.
On top of paid TV, you will see Fox News fill up with surrogates and elected Republicans attacking Trump every day, just like you did with Gingrich back in 2012. In that case some of the conservative media (notably Drudge) also joined in with the anti-Gingrich wave.
Do you really think ads will work? Bush's Super PAC already ran some anti-Trump ads. I have three reasons why it own't work:
A) The attacks have already been done. Trump is a known quantity. We've seen that people make excuses for him when they hear these attacks.
B) Mysterious super PACs and the Republican Party launching attacks against Trump will just make his supporters defensive and angry against the establishment. It will increase activity.
C) If you've ever read
Influence by Robert Cialdini, you may remember the doomsday cult story. The basic idea is that when people put a lot of passionate effort into something and then are shown definitively that they're wrong, they'll pour themselves into it even more, because they need reinvestment and affirmation that they are in fact correct. Social support is one major part of that re-affirmation, which Trump can provide in spades since he's the most popular candidate and has the most active supporters.
