my understanding of what you think is that these mega donors like adelson, the kochs, soros, etc., are donating because they expect/hope to influence policy to ultimately reap some monetary benefit. i am arguing that they expect/hope to influence policy because they wish to change policy for ideological reasons, with little to no consideration of any monetary benefit.
as a separate argument, i think it is fairly clear that frequently they have been able to achieve very little with their donations. but that is at least partially because the politicians/donors spend their money poorly. if you look at the kochs, for example, they seem to be directing their recent money more effectively (local/state elections, provision of legislative templates, etc). some of that may just be steering clear of trump, but not entirely.
