Whether or not he can win really has less to do with his popularity or ability to fundraise than you might think. The Democratic Nomination process is actually a bit more complex than it seems on the surface. It's about collecting delegates, not winning states. Barack Obama (David Axelrod & co.) understood this in 2007/8, which is how they were able to beat Clinton. If you recall, that was also supposed to be a coronation for Hillary. They're chummy now, but that was a really ugly primary which did a lot to damage Obama in the general election.
The strategy Obama used was to focus on states that Clinton didn't really care about and try to win them big, collecting a significantly larger proportion of delegates. For example, let's say a state has 100 delegates. If you win by a wide margin in the primary/caucus/etc. you may win 65 or 70 of those votes at the Convention. If you win a close race, you may only get 55. Obama collected delegates and played a much smarter game than Hillary, to the point where she remained in the race long after she had been mathematically elimanted - the media never acknowledged it and neither did she, but there was a point (late May/early June '08) where she had no possible chance of winning the race due to Obama's clinching the "magic number" of delegates.
The other part of Obama's plan was an absolutely beautifully executed ground game. Seriously, it is the gold standard to which all other Get Out the Vote efforts should be compared to. I'm not sure it will ever be done better, but now there's a model. The Obama brand was incredibly strong, he used the internet and social media better than anyone before him - there were online communities which had dedicated phone bank for Obama threads, targets, etc. The removal of the "go to the local crappy office and make calls" way of phone banking was blown out of the water. His team did incredible jobs in poor, minority, and under served communities - it was an extension of what I wrote above about the delegates. Obama's team understood that collecting a lot of votes which nobody usually bothered with would pay off, and it did. He won North Carolina! Tremendous effort.
The third heat for Obama was definitely fundraising - he was a machine, but it was only to power the other two. Romney had plenty of money as well, it's significantly more than that, and he can do it cheaply in the primary as well where money is less important. The buys in the states Obama won were significantly less than the ones Hillary won.