The problem with PHP/ASP/ASP.NET is that you have a lot of different configurations and versions that you need to support. With node we have lot more control over the environment and the server is build-in.
With PHP we always had to check which version is installed, are the required PHP modules installed on the server, which database drivers are installed, what server does it run on (nginx doesn’t support htaccess files which we use for routing). With node we don’t have this problem, we bundle all the required modules directly with it and we choose which modules we are going to use.