It's not just Mt.Gox. Everything about this currency needs to be more professional.
What you see now just looks like a hobby currency. Adoption is slow but I think professionals are turned off by the early adopters fortunes. No matter how you try to explain it, a lot of people don't like the fact that a new currency can be invented and this can happen.
Sure, early discovers of precious metals, oil, rare earths etc. get the same thing. But this currency has been invented out of thin air. I think there is still a great lack of confidence in it. It could yet drop and be worthless.
Bit of a chicken and egg situation.
Yeah I agree with your early adopter analysis. However, many of the first commercial websites grew into huge businesses (take books.com for example) and that didn't stop large scale adoption...
This seems to be the most common argument against it. I hear this comparison with corporations all the time.
But the thing is...BTC is not a corporation. And there are tens of thousands of large corporations. There won't be tens of thousands of new currencies. There will never be tens of thousands of commodities traded on world markets.
What's to stop someone creating their own new currency? And then miners make a load of money there too? And when the early adopters have cashed in, they make another new currency...and another new currency...then it starts to sound more like a ponzi scheme.
This is something that BTC proponents don't like to talk about. And it could ultimately be what makes this currency fail. All you need is a few more competing peer to peer currencies. Then, who is to say that they are any less worthy than BTC as a currency? As soon as that is made clear, all of these currencies will become worthless.
At least other virtual currencies and new country currencies are backed by gold (or at least to some degree). BTC is not backed by anything.