The difference here, I think, is that baseballs that have been batted are usually unusable again in a major league game, whereas the footballs still are.
Remember that a major league pitcher can often make a scuffed ball do everything but sing an aria on the way to the plate. The balls also don’t cost but about $10, so it’s not so bad to give them away in the first place.
Plus, it’s hard to take away a privilege once it’s given. The baseball fans wouldn’t stand for it if the league kept all the balls.
If you’ll watch any Major League Baseball game, every player (depending on when they are brought in/taken out) plays both offense and defense, except for American League pitchers and designated hitters. Even Bonds and A-Rod play defense. Are you saying everyone who bats should pitch?
Not necessarily, at least in the case of the Yankees. Off the top of my head, the only years in which they clear-cut would have won the AL East under the old arrangement were 1998, when they would have between an All-Star team, and last year. Otherwise, they would have been in tight pennant races with Cleveland some years (sometimes better by 2-4 games, sometimes worse by the same margin), and they would have been smoked by Cleveland some years.
This, even before mentioning that they made it in the postseason in '95 and '97 as the wild card and didn’t even finish with a record in the top four of the AL in 2000, when they went on to win it all.
In sum, the Yankees have no doubt been great in the past decade, and it is difficult to win three postseason series, but the new format has helped them greatly in getting to the postseason—and has denied what would have imho been a very good rivalry between the NY and Cleveland teams of the mid-late-90s-until 2001.
Sorry for invectifying your grand ol’ thread.