Yes, they did pay in for the $2 Billion, but I believe FIAT was demanding another $8B (or was it $12B) on top of that in order to become part of the GM family. Quite honestly, no one in Detroit wanted FIAT at the time, as this was still a company that was teetering on extinction due to poor selling products in the Alfa and FIAT lines. GM, at least in my mind, was correct in their choice for an engineering partnership, but for FIAT to actually think they were to be acquired by GM, that was a mistake.
...And while I'd agree now that GM isn't quite in the trouble that they used to be, the whole question of "used to be" pretty much was defined at that moment. They didn't have many (if any at all) that were truly competitive with the foreign-made models (this was when the Cavalier still roamed the Earth), they were teetering on slumping sales and dwindling stock prices, and generally didn't have a great direction as to what was up, and what was down.
If anything, the FIAT deal was the first moment in which Wagoner, Lutz, and many of the other board members kinda realized "Hey, maybe we aren't in as good of shape as we thought we were..." I mean, sure, they continue to be the world's largest automaker, and I'm certainly in the camp at GM that says they made the right decision to get rid of FIAT and get out of the deal. Furthermore, I think they made the right decision dumping Isuzu, Fuji, and Suzuki as well. I think I'm quite content brand wise where they are today, but more or less, its going to be about GM deciding who gets, and furthermore who builds, what and where.
There is nothing that I love more than GM, and the longer you hang around here, the more you will see it. My problem is, at least with other GM folks, is that I'm more of a realist in some circumstances, something that doesn't always occur here in Michigan. I do my best to tow the line, but when you've got stupid people still making stupid decisions in Detroit, thats a problem.
===
...And either way, even if GM did buy into FIAT, they wouldn't have gotten Ferrari. It would have been much the same situation as what we're seeing with Proton and Lotus over at VW, brands jumbling things around because they want this or that, but the good stuff stays away.
A Ferrari with a Corvette, much less the oft-rumored "hyper" Cadillac wouldn't do well for business. Its better that we let Ferrari be Ferrari, and build cars as mentioned in this thread.