Sounds like your family business is in that dangerous "middle zone." Your busting butt with all those employees and not making any more money then if you were a solo guy doing 50 lawns a week. This is a hard zome to get out of and there really isn't one right answer to solve this.
The easiest answer is this, though...get more work. Bill more. You stay in this middle zone and you'll probably die.
14' landscape trailer
60'' Exmark TT
21'' Personal Pace