I think part of it is getting the science right, and also part of it is putting the burden on women. Women's pill do a sh!t ton of things to their bodies...with hormones doing all sorts of stuff. But as soon as side effects are just a little too high of a percentage in trials for a male pill, then it gets axed.
From what Ive read the last 5 years, it doesnt seem like the big boys in the pharma community arent allowing enough progress with the male pill. Now, granted the hormonal side effects for men may suck a lot, and theres a different challenge when compared to the female body, but its 2015....we should have had one a while ago.
There are a bunch of science articles that would lead one to believe the old school view of birth control being the womans responsibility, is something that permeates the pharmacuetical community. But these dudes need to hurry up. Imagine if guys had a pill? Let a b!tch try to trap a guy once he has a condom and a pill in his arsenal.