I'm going to use the now cancelled Perfect Dark'' as an example but I think the point is applicable to gaming in general. Looking at the concept trailer, what was so hard about bringing that concept to life? It's an FPS with some Deus Ex inspiration and close quarter combat. The concept trailer showed some stuff that was clearly too scripted for real gameplay but that aside, we aren't seeing anything that hasn't already been made in previous games. Why was this literally too hard/impossible to make for a development team with MS money and backing? I think developers are literally losing the ability/talent to make games.

https://www.youtube.com/watch?v=ofUi9DR9sc4