I mean, you're basically asking why people don't do high-quality original work and give it away for free, as opposed to copying something that's successful and giving it away for free.

The answer in my mind is fairly obvious: it's far more difficult and risky to do high-quality original work and give it away for free. If you want to see more original innovative work in open source, the two main ways to achieve that are to either do it yourself, or to pay others to do it.