It is wrong to venerate our abilities and material objects too highly. That is how such things end up becoming idols. Solomon admonishes his audience to not allow whatever blessings or accomplishments that we may obtain get to our heads because they are in a very real sense not "original."
Anything that we own or have already done was once created or accomplished by people in generations past (such as the purchase of a home, furniture, the creation of artwork, or plowing a field). The author of Ecclesiastes illustrates the futility of life from a materialistic perspective. Thus, we see a reason for the usage of "vanity of vanities" and "nothing new will ever be done under the sun."
The human heart longs for something more than this life. It has a strong desire for something that transcends this temporal realm. The human heart finds its fulfillment in God. The world and the things therein are perishing. The things of our fallen world are subject to wear and tear. The human heart can only rest content in God.