I would beg to differ. Think about what you are saying for < 10 minutes and it might come to you.
"Software is easy. Since when? If you are not building something new yes it probably is. But then you'll probably wont be a startup."
Creating a rough prototype isn't that hard, if you think it is you are doing it wrong. Getting that prototype in front of real users isn't hard either, in fact if you use modern frameworks it will likely be as good as lots of other software out there. Creating great software is extremely difficult, but I know software companies making an absolute killing with hacky interfaces, no testing and poor qa.
My take: Ideas aren't hard at all. Neither is building a product. Almost no one does the necessary steps (e.g. steve blanks process) to get their product right, which boilds down to heaps of face-time meetings with the target market to truly understand their problems.