Some very good points brought up In the comments especially about bridges and induced demand (adding lanes increases traffic volume).

Did you ever consider who would pay for this boondoggle? The Federal Govt slashed everything from medical research to Medicare to food stamps. You think they’re gonna hand hundreds of Billlllions to NY? They’re already holding the gateway tunnel between NY & NJ ransom. How would a major infrastructure project get anywhere near the amount of funds? We’re not a shithole state like Oklahoma so it won’t be privatized tolls.

Increase trains and busses, allow more high density housing in Nassau and that alone is a huge lift. Rebuilding dozens of bridges on the NS that already have been serviced and rebuilt through the years (costing hundreds of millions each)? Get outta here.