Possible Clues:

• Likely lecturer retained by dunce not making money
• Like the United Way and NPR
• Type of organisation designed not to yield benefit or gain
• Smithsonian, for one
• Amateur? Well, there's no money in that!
• Type of organization, such as the United Way
• Amateur in good shape, not gaining surplus pounds
• Number willing and able to invest in advocate? Nothing to gain by it!
• Like public libraries
• Many a charitable organization