This scene is often misinterpreted.
Zoro is not putting Liffys dream above his own.
On the contrary.
What this scene really shows is:
Zoro says that if he is unable to even protect Luffys dream then his own dream would be impossible to reach anyways.
This makes it sound as if Zoros dream is above protecting Luffys in terms of difficulty.
"if I die here then I am a man who could only make it this far"
Zoro is well aware that he might not have what it takes to become WSS.
His willingness to sacrifice himself for Luffy only shows his compassion and that he is able to accept complete defeat. And nothing more.