I like how passionate Marvel are about making an Ant-Man film
Marvel co-president Louis D'Esposito
D'Esposito continued, “I was there when he made the test reel. I now know how it works and it's going very methodical and planned. First, he designed the concept, then the storyboard, then he produced an animatic, so he knows exactly what he'll turn. Every morning we visited him, and he had added new material, which we then looked at together. He is a passionate filmmaker and it that's contagious. We've only looked at it yesterday and every time we see it, then we think, ‘Wow! We can not wait to make this film!’”
That makes me think they must really thing Edgar has something worthwhile if they are excited about it and willing to stick by him this long to make the film.