All new technologies are first paired with non-risky material.

So they use a non-risky script, with nothing objectionable in it.

Once the technology matures you can use a better script. The price of better is that sometimes it's worse, that's why it's a risk. If it was a sure thing everyone would do it, but it's not easy to create something great. You can try, and sometimes you'll make it, and other times you'll flop.

Which is too much of a risk for a new technology - better to have something good enough, with little risk.

Remember: Everyone thinks what they are doing is great. But if you are wrong, and it's a flagship product you are doomed. For example http://en.wikipedia.org/wiki/Heavens_Gate_(film)