He literally says it's worthless through a series of metaphors as he goes through trying everything he can think of.
This could be considered reasonable if only familiar with modern translations like the NIV that use the word worthless and meaningless often in Ecclesiastes. Said view is hard to justify however when onward from 2 wisdom is called a tov and associated with other things as higher than them. Wisdom being expressed as a tov alone is an explicit statement of its worth in the view of Qholete when by definition a tov is a productive thing or a thing with value.
English translations exaggerate Qholetes use of paradox from something disjoint to something nonsensical when taken as whole. Unsubstantial, ephemeral, or elusive are more appropriate translations that remove the paradox and show in the microcosm of our own existence even things considered tovs like wisdom are temporary. The temporal dimension seems to have considerable importance as 3 is dedicated to it and states the difference between tovs in the Macrocosm of God and the microcosm of Man.
Hevel physically translates to breath but invokes the temporary so while Man has hevel God has ruah which is eternal breath, but tov is found in both. The symbolic tradition is fully alive and upheld in Ecclesiastes. That may express why despite having a more peculiar poetic prose and controversial philosophy it remains consistent with and adds depth to the other texts among the Writings.