You don't need a perfect room to appreciate a projector with dark black levels, that is something often misunderstood in this forum.
Once a room gets past a certain point in conditioning, you'll actually notice that bright scenes are benefiting more as the room gets darker, as opposed to how far those small improvements in the room help out the dark scenes. ANSI contrast is affected by room conditions more than on/off contrast or even the black floor. Sure in a better room the black floor is going to look lower, but the whites and blacks will both drop down, and projectors can only go so black, so a perfect bat cave helps, but saying you only need a projector with higher contrast if you have a perfect room or a perfect screen is definitely not right. The higher on/off contrast can be seen in a variety of different room conditions.
One reason for this phenomenon being seemingly backwards is that bright scenes are pushing more light off the screen which washes back into the room, so if you have a room that is 95% darkened but has a few reflective surfaces (like maybe a single piece of bright furniture), then it may show almost no reflection in a dark scene because not enough light is being bounced off the screen, but then in a bright scene the entire room lights up more, that is why ANSI contrast is washed out more in bright scenes from rooms with white walls and what not, even more than black levels. Now if the room is too bad, the entire image will look washed out and both bright and dark scenes look bad.
The Da-Lite High Power as well as some gray screens with positive gain will help preserve ANSI contrast for people with imperfect rooms. These are far from being expensive screens, you can get some HP screens at moderate sizes just over 100" for under $300.