Thats because we have tried it the other way. Its called waterfall. The problem is, the process is too slow in such a fast moving industry. If you are building

Thats because we have tried it the other way. Its called waterfall. The problem is, the process is too slow in such a fast moving industry. If you are building a bridge, you dont have the problem of being half way done and all your customers say, "nah, nvm there is tunnel that just went up, that can kind of solve my needs. I will use that one instead."