Ango,
Indeed, they bought the whole thing wholesale. The best way to remove a threatening movement is to lead it, this is quite clear. Whether its "ersatz" salafism and there's some "true" salafism in hiding somewhere is irrelevant. The mosques Saudis fund and establish worldwide sing to Saudi choir, not to the choir of some "the only true and real" Salafism, which exists only on paper or in Muslim history textbooks.
I still don't understand where and how you think the Salafi groups are getting their funds from and who and how sponsors their training, i.e. their was this notorious story about an American after visiting local Mosques receiving a pre-paid trip to Afghan training camps. So who's sponsoring the whole thing if not Saudis? Do you seriously believe in a movement without a leader (since you think Saudis are merely hijacking it) which just suddently "springs up" out of nowhere, on its own and gains worldwide fame in the Muslim world?
With regards to your last point, this is more descriptive of the 1960-1980's period, because right now Saudis basically control the oil market and a large fraction of US economy (with direct investments in US economy and indirect manipulations of global markets), US economically is strongly dependent on Saudis for their own economical well-being, while Saudis depend on US for military protection, so it has grown into an alliance of equals since 1990s. The reason I believe US moved against Iraq in Kuwait, is because Saudis
told
them to.