Technically, yes that is correct. I usually prefer to focus on only one sport at a time, but sports are seasonal so you want more than one and sometimes they overlap. Technically the most profitable way to go would be extremely selective and only place maybe 1 big bet per year at maximum value...but that would also give you high variance.
A lot of smaller bets over the course of a year takes the variance out and gives you sustainability. Having multiple sports also gives you diversity and that's no different from investing where diversity can be a very good thing for reducing variance.