«إِنَّ الْإِنْسَانَ لَفِي خُسْرٍ»
Indeed, humankind is in loss.
Inna introduces emphasis, and the lām in la-fī khusr further strengthens the assertion. The prepositional phrase occupies the predicate position. The wording reinforces one judgment through more than one grammatical means.
The exception in the succeeding passage qualifies its scope. A careful reading does not isolate an emphatic statement from the passage that explains its reach.