...but it just seems reckless to simply commit offensively and hope that someone on your team can get back in time if the opposing team has the position advantage and good strikers.
Comes down to communication and knowing your teammates. I've played with random people who understand and appreciate rotation. If I'm playing midfield/defense and I see a playable ball to strike, I'll go for it knowing the furthest back person will rotate back. If I'm playing with ball rushers that don't rotate, then I'll continue to play midfield and only go for the most opportune strikes. It's not reckless if people communicate or have a good feel for how the others play.
Gibbs, the main defender on Cosmic Aftershock, spends good chunks of time in the offensive zone. He doesn't stay there, but will take a shot when it's advantageous and peel back right after (often swiping a corner boost in the opponent's zone so they're deprived of it for a while). While he's up, one of his teammates is always back to play defense. I've also seen both of this teammates play goalie until he gets back when there's pressure in their zone.
I play 2v2 with my son and we rotate on both ends. 2v2 is quite different from 3v3, but either way it's much more advantageous if the closest person with the best angle clear the ball on the defensive end. So if the person in goal has the best shot, they have to let the other person know they're clearing so the other person can rotate into the goal. I give the AI a lot of flak, but one thing I like is how it will leave the goal and go clear the ball if you come into the goal (and since they're terrible in goal, it's usually the wisest move).