Perhaps I wasn't clear, Earth is _not_ a closed system. There is energy being pumped into Earth's biosphere from the Sun. But given enough time the sun will exhaust it's hydrogen, turn into a red giant engulfing the earth (maybe), eventually leading to our solar system trending to a low energy state. But that may very likely be interrupted when Andromeda and the Milky Way merge leading to a time of increased star formation (high energy state). Ultimately yes, the universe will trend toward a low energy state, in the very distant future (deep time) the universe will be nothing but slowly evaporating black holes each many billions of light-years away from each other.

BTW I dislike the term "disorder" in the context as it implies something more akin to chaos, which is not really the case. Some would say a universe with nothing but evenly separated atoms expanding away from each other (the real end state) sounds quite "orderly".