Also, mostly everything is a command in Emacs.. So, when you press "a" it basically translate to "call the function insert-character 'a'". So, in a way, Emacs keybinding are really just a little api over the real commands.
In vim, it's a totally different philosophy. Everything is based on making the editor as efficient as possible. Yes you can hack stuff and go on IRC with Vim but conceptually, it's not what it's been designed for and you'll likely hit lots of problems down the road and will have to use all kinds of hack.
So, is putting emacs in Vim possible? Vimscript, even thought being an abomination (my opinion), could implement elisp.. with all the necessary wrapper. So, maybe that'd be possible.. but rather useless.
Finally, my personal opinion.. with Vim, I really felt like "tweaking/hacking" it when I tried to customize it. For instance, I'd try lots of different mapping/paste things found on internet and hope it'd work. Sometime it'd fail for obscure reasons.. and you'd add another hack on top of the hack to fix it.
On the other hand, in Emacs, I feel like I'm really coding my editor as I want it. I'm not surprised by its behavior or its interface. I.e. You can bind an event to call a function when a buffer opens. If you know a little bit of lisp, you'll feel right at home. And if not, there's no better way to get started with that fabulous language.