The cost will only keep going up. It's a valid question do we just plunge ahead anyways? The 2nd Ave did get opened after all, should we cease any expansions to the subway ever, or expand (at great cost)? I don't know the right answer, the costs are absurd and ideally work would be done now to reduce these costs through corruption investigations and reworking how the MTA does bidding and contracts. It also raises an interesting equity question, we spent all this money to connect the UES with the Second Ave Subway, plus largely white suburbanites with ESA, where's the billions to connect more minority neighborhoods like Harlem, and the future expansion to the Bronx?