SUDDENLY, the nation's most successful professional sports town is, of all places, Philadelphia. Just three months ago the baseball Phillies were winning their first World Series. During the 1980-81 season, Philadelphia's professional basketball and hockey teams have, between them, lost only 22 times in 100 contests. Tomorrow, the professional football Eagles of Phiadelphia are the betting favorite to defeat the gypsy Oakland Raiders in the Super Bowl, to be played in New Orleans' Superdome.

Most professional teams consider moving when paid attendance begins to fall off. The Oakland Raiders, who have had nothing but full-house crowds for the past 10 years, tried to move to Los Angeles last year. The league blocked the move, and the city of Oakland sued to keep the team in the Bay area. Society's rampant litigiousness has reached the gridiron.

Over the past 18 years, Oakland has had the most successful winning record of all the teams in professional football. That happens to be the same number of years Al Davis has had a major hand in running the Oakland team. Mr. Davis and Oakland are given to picking up players who have been given up on by other teams and some even who have been given up on themselves. On Sunday, Oakland will be led by one such rejuvenated star quarterback, Jim Plunkett.

Philadelphia, a team with more talent than panache, is very driven by Coach Dick Vermeil, who as a college quarterback once played an entire game on a broken ankle. The caritable analysis of such a performance would be that it proves determiniation and character. Coach Vermeil had earned the reputation for working his team and himself unbelievably hard. The Eagle, with their barefoot kicker, are a team without big names but with a very impressive record.

New Orleans, like the New Orleans most of the time but especially during Super Bowl week, has had a full week of parties and receptions to celebrate one three-hour football game. Dick Vermeil is passing up all the pre-game festivities and apparently not regretting any of it. He said: "To me there's only one way to enjoy a football game, and that's to win it." If it were any other team than Al Davis' Raiders, we are certain that Dick Vermeil would enjoy himself fully. But the Oakland Misfits and Irregulars simply cannot be written off. The 1980 season officially ends with this game pitting the discipline and dedication of Philadelphia against the dark-alley high jinks of Oakland. Philadelphia by three. But whatever, it's the very last real bowl game, honest.