Yeah ive had that thought before mostly related to the NFL and it's shift toward more games
They're at a 17 week regular season now and it's a matter of time before it's 18.
Problem is these leagues and the players dont really want to cut down the schedules because that's taking money out of everyones pockets but playing more games really isn't good for the players long term health. A solution like this could work
In the NFL, they increased the regular season by 1 game, but managed it by cutting the number of weeks of pre-season games. It used to be 17 week regular seasons, each team playing 16 games, and a 4 week 4 game preseason.
Now its a 18 week 17 game regular season and a 3 week 3 game preseason.
Also the NBA with its in season tournament is able to work it due to the number of times teams in the same conference play each other. They play teams in their own division 4 times during the regular season, and 3 times against teams in their own conference but only twice from the other conferences. Hence they don't have many logistical problems. Trying to run a comp like it in the NRL with teams only playing some teams once in a season makes it impractical.