I may not have a full understanding on the project, but I have doubt.

One benefit of Push is that the server can potentially generate a group of responses together, which can be much cheaper than generating them individually. When prefetch is used instead of push, the decision on when and what to fetch is on the client, so if the server could generate them as a group, a proxy like Vulcain would have to buffer the results somehow until the browser asks for them, which is not ideal. I might be wrong, but I don't think their server ever intended to fix the Query+1 issue.

If Vulcain and Push already worked well for you in the past, maybe it's still as effective without Push though!