What evidence do you have that emacs is easy to use? I assert that if you asked users who had never seen emacs to use it to create, save, and reopen a file, the vast majority would not be able to do that.
You can assert whatever you like. However, I have introduced emacs to several users over the years, and many of them had never used anything other than MS Word. In almost all the cases, emacs became the primary editor of choice. If you look at the posts in gnu.emacs.help, you will see that most of them are from novice users and not geeks. In case you haven't used it, emacs under windows has the same file open dialog as any other application.
If the application I use -- open source or proprietary -- doesn't do what I want, I will use another application.
Your wants must be really narrow.
Even for a skilled developer, writing code is the least efficient way to accomplish a task. The F/OSS community needs to understand that the ability to review and revise source code is utterly unimportant to the overwhelming majority of software users.
Have you even used emacs? The way it works is like this--you write some function to do a particular task, and load it without leaving the editor. If you don't feel up to writing code, post in gnu.emacs.help using the built in gnus news reader, and someone will write it for you. People don't simply sit around doing edit compile cycles.
Yes, emacs has been widely ported. That fact alone testifies to a lack of innovation. Rather than coming up with something better, developers on those other platforms simply ported existing code.