It takes more than one minute to sell a project regardless of how good your elevator pitch is. The elevator pitch is an introduction and an introduction is successful when you get beyond the introduction. In other words, a successful elevator pitch gets you beyond the introduction to a second meeting.
“The best elevator pitch doesn’t pitch your project. It pitches the meeting about your project.” — Seth Godin, Seth’s Blog: No one ever bought anything on an elevator
This is a distinction worth remembering as you prepare / review your elevator pitch. An elevator pitch concludes with an ask for a second meeting and your pitch needs to make the listener want to talk to you again.