Why has personal fund raising worked for more than 50 years?

United Way's New Way - Forbes.com: "United Way also got blindsided by a changing charity world. The number of nonprofits soared, rising 40% in a decade to 1.8 million and vying for money. Many had a single-issue focus--a specific disease like juvenile diabetes or a narrow cause like open-space preservation--that created close donor identification, loyalty and wallet-opening. Some donors found United Way’s broad funding too defuse."