The idea that we can bring the majority of third world countries out of poverty by throwing money at the problem is a fairly naive point of view. Past experience has shown it to be ineffective (take a look at the African debt issue).
First up - to whom do you give the money? Poor countries invariably have corrupt Governments, and passing tens/hundreds of millions to corrupt Governments only goes to line the pockets of corrupt politicians, and those in the favour of said politicians. Very little if any reaches those in real need.
The second option is to pass money directly to those in need. But how is this to be done? It's not like they have a bank account that can simply be creditied... And being (for the most part) at the mercy of local militia, anything substantial that they are given is simply taken away.
The only viable alternative is direct and sustained food-aid / medicine provisions. But this is NOT a long-term solution... This requires millions of foreign aid workers to be present in countries where they are often unwelcome (by local militia and Governments I mean - not the people who will clearly welcome any help they can get). This still does not help anything more than day-to-day survival. It does not help people to "build businesses" or otherwise prosper.
In an idealistic world, yes - the amount of sheer capital (in terms of absolute resources) needed to solve the problem would be relatively easy to pony up. But in the pragmatic world we actually live in, there is no way to use these resources to solve the problem. Until corrupt Governments are replaced with stable Governments, who can look out for the best interests of their citizens and protect them from local militia, rather than simply lining their pockets, there is no way to help those in need to build up long term stability.
This leaves us with the option of invading country after country in an almighty military crusade, which would be immensely costly in terms of lives, and could easily spiral out of control, or simply sitting back and hoping for change. Clearly the world is taking the latter approach.