The Dodgers were the first team to draw 3,000,000. That was in 1977. Kids’ tickets were $1 back then.
Davey Lopes, Reggie Smith, Rick Monday, Steve Garvey, Bert Hooten, Ron Cey, Manny Mota. THAT was baseball.

That was my team. My brother (a Reds fan) and I would eagerly await the arrival of the Sporting News because it had team and individual stats you could not find anywhere else. One of the stats was attendance and as I recall two million per year was rare and many teams had abysmal attendance compared to recent years.
My best friend’s older brother played high school baseball with Ron Cey in Tacoma, mid-60’s IIRC. The Penguin.