It's actually very complex to convert that amount of money any time, let alone working with Bitcoin.
With respect you don't seem to understand the process. Who converts btc to USD? No bank in the world does this. Mt-Gox does the exchange on their own books in a split second when you click 'SELL'. That is not very complex.
I really do understand the process. It's not the conversion that's the problem, it's the banking. And it is complex because you don't want that money being locked out or to have an unknown transfer time which can be weeks or months. Unfortunately VMC are US based - this is all non trivial.
I already pointed out emergency transfers can (apparently) be requested for 5% on Gox but it offers no guarantees and is definitely not as easy as you say. Then you have to be allowed to keep and use the money in your bank, which is also not as easy as you may think.
On top of that, at the point where the IPO was successful, Gox were in a worse situation. Even if it were more feasible now (and it's only slightly so), then I'd expect that the majority of the funds would have been converted already.
Running a business you need to know when you'll have your money. There are risks whichever way you look at it, but the risk of never getting your money (Gox) or it being delayed possibly months is the worst one. That was the situation with Gox at IPO time and it still more or less is. That's why Gox has such a premium. It doesn't work like you say it does - other evidence being the lack of meaningful arbitrage.
Tradehill is set up in the US specifically to deal with the US regulatory/banking situation and high value traders (/dark pools), but AFAIK Tradehill are very much a work in progress. You can actually go meet Tradehill in the US easily. I was at the Bitcoin London talk where they said they had more lawyers than techies, and I spoke to several people at the conference who are working in this area of Bitcoin.
When you deal with dark pools and large amounts, you also have to negotiate timing and rate.
With respect (genuinely, as I can see you're a big ActM supporter), I don't think you understand the intricacies here.
Finally, we don't even know if the money has been converted, all we know is that he deail hasn't been signed off AND paid for, since that's the point at which I'd hope to see a press release.
(Few minor edits made)