Former NFL stadiums and what those properties look like now
Of those listed I have been to Shea numerous times. I have been to Busch once (saw Lou Brock play on Lou Brock Bat Day).
I saw Sam Mills run back a handoff at the Meadowlands.
I wish the Polo Grounds was still up when I was around.
After the original New York Giants MLB team left and relocated to S.F. in the late 50's, following in the footsteps of their once-crosstown rivals, the Brooklyn Dodgers, their wasnt really much of a need or major functional purpose for keeping the Polo Grounds or Ebbets Field around anymore because, by the mid-late 50's, both stadiums were close to or over 40 years old, had crumbling bleachers, stands, were terribly out-dated, some of their amenities were typically found in late 19th century MLB ballparks. IIRC, the Polo Grounds did serve as a temporary home stadium for the expansion New York Mets while their then-new stadium, Shea Stadium, was being constructed for them and also the 1964's World Fair.
What's interesting is that if Dodgers had accepted Robert Moses offer of a new stadium in Queens ( close to the eventual Shea Stadium), the New York Mets are never created as a sort of substitute for the departing Dodgers, Walter O'Malley and Moses didnt have a great working, professional relationship and O'Malley's insistence that any new stadium for the Dodgers had to be in Brooklyn, rather then anywhere else in NYC, doomed any remaining chance of Dodgers ever remaining in Brooklyn.
Before the original Meadowlands opened up for the 1976 NFL season, the New York Giants were sort of a homeless, desperate, vagabond team who didnt have a home stadium or played in 3-4 different places from the early 70's to 1976 as they moved out of Yankee Stadium as it was being renovated in 1973-74 (?). Since NYC had some well-publicized, documented financial issues concerning public funds and the fact they were tens of millions of dollars in debt by mid-70's, moving to the north Jersey suburbs, swamps of Bergen County seemed like a very rational, sensible move.