When someone doesn't say yes, they'll often give you a reason.
A common trap: Believe the reason.
If you start rebuilding your product, your pitch and your PR based on the stated reason, you're driving by looking in the rear view mirror.
The people who turn you down have a reason, but they're almost certainly not telling you why.
Fake reasons: I don't like the color, it's too expensive, you don't have enough references, there was a typo in your resume.
Real reasons: My boss won't let me, I don't trust you, I'm afraid of change.
By all means, make your stuff better. More important, focus on the unstated reasons that drive most rejections. And most important: Shun the non-believers and sell to people who want to go on a journey with you.