Price is a major factor. That's why all the 400"ers have been one
trick pony types, and with launches. A traditional out n back 400+ or
500+ coaster would be awesome, but the cost and amount of land for
that one ride would be incredible. But at least it would be a long
lasting and good ride on its own if the record would be broken. I
believe it will happen someday, most likely at Cedar Point.