And even then, as a coach, 3x/week is usually not enough. How to huddle, play names, formations, actually running the plays, proper tackling, proper blocking, handoffs, catching, game situations, conditioning, etc.......3 practices can fly by in a hurry.
3x per week for any other pre-HS sport and I'm right there with you. I've coached a lot of baseball, basketball, football, and flag football. Tackle is the only one that really needs 3x/week+ to get the kids ready for games, ESPECIALLY early in the season like right now.