X Marks The Block

Just out of curiousity, and I support the streetcar project in prinicpal, but there comes a time when the costs to construct outweigh the benefits. I believe the initial price tag was 115 million, now they are saying 150 million, could go up more. Everyone essentially has a price, in everyone on the forum's mind, what figure do they have in their head that if the streetcar costs rose to that level, it would not be economically viable or make sense to build? $200 million? $500 Million? $1 Billion? Or it is worth building at any cost because the benefits cannnot be quantified and that once it is built the value to the community will be priceless no matter what the value? Interested in hearing people's thoughts