They may have been so conditioned to being on top that anything less disappoints.

They may have been so conditioned to being on top that anything less disappoints.

conditioned to....something..应该可以解释为 under the condition of something(在这something的情况下).......

that 引导结果状语从句，从句结构： anything less（主语） disappoints（谓语）。 anything less = anything less (than that) = anything less (that being on top)，比高高在上稍微逊色 这里disappoints是不及物动词，使人失望，这里是令他们失望的意思。

condition to （使）习惯于。类似于look forward to 一样，后面不是跟动词，而是跟名词，所以就是being 而不是be。