just popping in briefly, so apologies if I don't get involved in convo,as off again very soon,... but charities tend to be started up by small groups of people who are passionate about a particular cause (usually because they, or someone they care about, has been affected by the problem, but sometimes out of sheer altruism). Hence the oncologist that policywonk knows of may set up a particular charity specialising in lung cancer research.
If that charity does well, it may grow and grow. (Think of the Roy Castle charity). And in ten, twenty years people will be criticising it for being 'too marginalised'...not supporting people with curable lung cancer, or a particular type of cancer not covered in its remit, or lung disease per se, not campaigning for the right things, being 'too big', too top heavy, etc etc.
It is the idiosyncracies (sp) of charity work - charities don't emerge because of some grand plan, but due to the hard work and dedication of a small few. This grows to a larger staff, all set on campaigning for the particular cause that the charity holds dear. But it is an organic growth, and charities seek the funding where they can - hence building a 'brand' and focusing on key messages.
There is a growing voice within the sector for charities to merge and stop duplicating - age concern and help the aged have just done it, and Macmillan Cancer Support and Cancerbackup did it a few years ago.
You have to remember that many of these charities rely on the strength of their name within the public psyche to raise much of their funds. To merge with others is to risk a dip in this ability to raise funds. Many of them know that this is the way forward, but politics, fundraising and different agendas make it more difficult.
Stick with charities, be patient... remember they're not perfect, and they're not hard-nosed businesses - though they are often run well, with an eye on low 'admin-to-spend' costs. And get involved, add your voice, and help them to change by telling them what their supporters would like to see.