Most of the stalwarts you mention had been built to depend on more or less huge systems where the webserver/appserver was in a central postion (Apache, J2EE or

Most of the stalwarts you mention had been built to depend on more or less huge systems where the webserver/appserver was in a central postion (Apache, J2EE or IIS), node had a certain minimalness combined with client/server code sharing going for it and Go had the whole "be as cool as Google" vibe off it (also not tied to a big server but being self-contained) and both of them meshed well with a certain microservice trend of those days. Yes, there was a certain hype driving them but they also fit into the "devops" paradigm shift where the unit of management became a container/application instead of begging a BOFH to configure part of a "large" server that were suddenly becoming commoditized (The desire wasn't maybe so much a clean slate as to not be held back by sysadmins).