Development tools have dependencies. This is expected and even desired. That you are having problems with the installation in no way invalidates the benefits.
Furthermore, your complaint about downloading a lot of tools is immaterial. If PhoneGap created a single .exe, it would take as long to download, because it would have to bundle those dependencies. Never mind that node, cordova, and ant are all pretty small -- if they are taking hours to download, you've already got an issue with your network, your ISP, or something else. The things that are likely taking a long time to download are the development SDKs (like Android)... /which you would have to download anywhere, single .exe or not/ unless you use PG Build.
Let's also not forget that there are lots of configurations out there... not everyone is using your particular version of Windows with your particular set of installed softwares. Because PG is a cross-platform utility, it makes sense to target a consistent foundation, and since /node/ runs on all the targeted OSes /and/ because it deals with JavaScript (which is our language-du-jour), it only makes sense to require it as a dependency. PhoneGap is just a fork of Cordova, hence the dependency there. Ant is used for generating compiled output: lots of build systems require it, not just PG. As to "what else" -- can't help you there if you don't say what it is. I'm guessing the Android SDK and such, which while large and perhaps painful to work with, is still something you'd have needed to download to build Android apps locally.
Finally, there is a simple "installation", in a way: use PhoneGap Build. Compilations are done in the cloud -- you just have to provide a .zip or a link to a repository. You can also use the PhoneGap CLI to deploy to Build, in which case you don't need ant and the Android SDK (but still need node).