Pinto-
re Shubert rates: the post to which you replied was mixing apples and oranges, talking about the Little Shubert, an off-B house, in the context of Broadway theatres. the Little S is more expensive to do a show in because of the union contracts in place at the venue. Broadway rents are mostly revenue driven, and the same. Fixed rents vary by venue because of size and related considerations but they are not a significant part of the expenses of a show (unless it has no revenue).
re new theatres: it is a 2 edged sword because of supply and demand: there are times when everything is full but there are also times when there is a lot empty, and for long periods. Adding to supply exacerbates that. The landlords do not generally think they would benefit from more supply, and it is hard to identify viable shows that do not find theatres. Name one.
The Times Square Church is not for sale. To buy something requires not just a buyer but also a seller.