Just goes to show how little you know about real-world software development, software of any significant complexity takes ALOT of money and time to develop properly.
When considering ED and the feature set FD have stated they want to deliver for it, I would not be surprised if the full product does take 20+ years to complete nor would I be surprised if not all the wish list items are implemented. What FD have done is start from a workable baseline that counts as a viable product and release it in order to gain enough funds to continue development. There is probably no way ED would be here today if FD did not release the product when they did.
As for what they have done in terms of updates since release, maintaining a live product (at least on the PC) and updating it at the same time is a costly affair - often more so than the initial development due to platform changes through the life of the development (amongst other things). Certain things can be mitigated to a degree but it does not change the fact that not everything can.