(answer to the question "What is the business model for a Think Tank?")
There is a room between dark conspiration theories and total transparency. Basically, a Think Tank is an Outsourced Lobbying Tool, a Non-Profit Outfit for big profit companies (kind of "His Master's Voice" without the Marconi logo).
Some are Hot Air Factories specifically designed to accelerate Global Warming. The funding system is similar to that of a lobby, the casting generally slightly different. You just have to offer a few big lunches to a few big names.
Some actual non-profit initiatives (people who prefer the think thing to the tank thing) prefer the Foundation business model for an easier financing (in : taxes - out : expenses of VIP members who would not join otherwise) and a clearer legal frame.