I think it originates from the observation that all machines "leak" power in the process of performing work. Vibrations, thermal conduction, infrared radiation,

I think it originates from the observation that all machines "leak" power in the process of performing work. Vibrations, thermal conduction, infrared radiation, etc all tend to decrease efficiency and hence increase entropy (in the form of heat loss, mostly). Entropy can of course be lowered by bringing a measure of order to a given "isolated" system. At much larger scales however the vast number of possible microstates dominate, and thus the "inevitable march toward disorder". Also bear in mind that "entropy" itself is a fairly general concept which can be applied to just about any field. Information, for example, can expressed in terms of entropy. (Which obviously has nothing to do with the "thermal entropy" of physics.)