We are not satisfied with the conclusion that life is meaningless, we want there to be purpose and we feel that there must be purpose. So the Teacher seeks out where that purpose is. He has found that wisdom does not provide the purpose, now he looks for pleasure. It is probably true to say that in our age there are more folk who seek to get meaning in life out of pleasure than out of wisdom! The Teacher just sought to enjoy himself, getting drunk and "embracing folly", but this too proved to be meaningless. Pleasure does not satisfy and just leaves us feeling empty.
Next he embarked on great projects. We set ourselves a goal, something we believe to be significant, and devote all our efforts to achieving that goal. The Teacher embarked on building houses and plating vineyards. These were carefully and wonderfully designed, and "project managed". He acquired much wealth, and many slaves and entertainers. At the same time he kept his wisdom. So he did all this in a thoughtful manner.
He fully devoted himself to all this, but at the end came to the same conclusion, it was all meaningless.
Wisdom having proved unable to provide meaning, he tried the opposite, folly. He concluded that wisdom was better than folly, but both the fool and the sage reach the same end, both die. In purely materialistic terms the final outcome of life is exactly the same for every human being. Rich, poor, wise, foolish, strong or weak. The final verdict of this life is "dead".
This all led him to hate life, what was the point of all the effort and hard work in life if at the end of it we all die? And even the things that for a time give satisfaction or pleasure, they too come to nothing.
At the end of this chapter he comes to the conclusion that the best we can do is to eat and drink and find what satisfaction we can in our work. And this comes from the hand of God. Without God there is no point to life. He is the One who gives meaning.
At this point the Teacher has come to a rather lacklustre conclusion. It is not like the great hymns of praise to living for Christ that we find in the New Testament letters. It is more just a "let's make the best of it" conclusion. He even declares that this too is meaningless. This is not the final conclusion, certainly not the final conclusion of the Bible, but there are times when we cannot see the end, when we are not full of the presence of God. In those times the answer often is just to get on with things, knowing that at some point God will bring more light to our lives.