We can always use native prairie plants instead of more traditional ornamentals even if we don't have a "proper prairie". They are no more difficult to grow, expensive, or hard to come by if you start with seed. Planting them is beneficial in any amount I think. There is a lot of private residential land in this country that is currently pretty much useless to wildlife.
Keeping a large prairie completely free of exotics and invasives is no easy task I'm sure. But, who says it has to be perfect. Anything people can do to work towards something better, has got to be better than doing nothing at all. Even worse than total neglect is using the current mainstream techniques of maintaining large expanses of watered, fertilized, poisoned, and mowed... lawn.
Burning would make me nervous as well, and there is nothing saying you have to do it to grow prairie plants. Even at that prairie haven site they only burned some areas initially and have dialed it back or stopped completely from what I read. They said that while it is beneficial for the plants, the good insects took such a big hit from regular burning. In nature no area would burn every single year anyways.
