The Yankees’ new ballpark, due to open next April, is nominally worth about as much as the Florida Marlins, Tampa Bay Rays, Pittsburgh Pirates, Kansas City Royals, and Milwaukee Brewers combined. This isn’t a rhetorical assertion; going by Forbes magazine’s most recent estimates of the values of various teams, these five clubs are worth about $1.3 billion put together, about the same as the new Yankee Stadium.

For this sum, one could buy a baker’s dozen of Joint Strike Fighters, or the Chicago Spire, which upon its completion in 2011 will be the tallest building in North America, or dinner for 13 million at a nice restaurant. Or just pay Alex Rodriguez’s contract four times over, and still have money left for Johan Santana. To say that the new park is a monument to excess, entirely built upon excess, is just to make a plain observation.

During the first home stand of its final season, then, the old Yankee Stadium, caught in a torrential, Opening Day-delaying rain or not, takes on some of the quaint charm of old time ballparks such as Fenway Park and Wrigley Field. It isn’t simply a matter of misty sentimentality and memories of everything from Don Larsen’s perfect game to that lady in the right field bleachers who wore at least two dozen Paul O’Neill buttons and spent whole games shouting, “Pawwwwllliiee! We love you!” It’s also nostalgia for a time, such as 1998, when the excess was a bit less excessive, tempered by the memory of recent failure and by expectations that, while burdensome, were not like those that meet a team about to move into a $1.3 billion ballpark.

Ten years ago, when Derek Jeter was younger than David Wright is now, the Yankees’ payroll was not only about a third of what it is now, it wasn’t even the highest in the league. The team, not yet a dynasty, had won only two World Championships in the previous two decades. The general bluster and monumentality that surrounded the team then — think portentous public announcements, eagles, horn music, fake Roman architecture, and Old Timer’s Day — came with a wink. Playing in the House That Ruth Built, always a far more ramshackle structure than its legend allowed, the Yankees wore their heritage proudly, but also lightly. No matter what claims were made for the team, it still played in a boxy, 1970s-era stack of brick and plaster across the street from a bowling alley.

Old Yankee Stadium was, and is, a work of collective imagination, an idea animated by the Yankees’ insistence on its magisterial properties and by their fans’ willingness to suspend the evidence of their eyes and accept the Yankees’ claims. No ballpark — no vanished Polo Grounds along the river, no Ebbets Field by the trolley tracks, and certainly no Shea Stadium, avatar of a city of the future that never arrived — could ever so well represent the idea of New York, a city whose greatness is sustained less by its natural advantages than by a communal act of will.

The stadium’s last year will mark the passing of many things, but perhaps most of all it will mark the end of Yankeeland as a wonderful act of pretense and belief. New Yankee Stadium will be no more and no less than what it actually is: a preposterously expensive representation of a boom time for the city and the Yankees, one that may have passed by the time the place opens its gates. The old park is sustained by the myth that Ruth built it, and the truth that it rose as an expression of the city at a time when it was announcing itself as capital of the world. The new one will be sustained by the myth that it was built by Jeter and a city made rich on sub-prime mortgage profits. One myth isn’t necessarily better than the other, but one is certainly more evocative.

Ballparks are places of business that exist to make money. This was true of the stadium that will be abandoned after this year, and it is certainly true of the one due to open next year. The sustaining myth of each is mainly a marketing gimmick, most useful for packing in the people and getting them to part with their cash. So far as the new park will doubtless prove more effective at that, its myth, no matter how drab it seems in contrast to the one that preceded it, is more useful and therefore better. But throughout this season, it won’t just be the truest believers who will mourn the old ballpark. Those who see the flaws at the heart of its legend will mourn it as much as anyone else, and perhaps even more so.

tmarchman@nysun.com