If the Massillon-McKinley game isn't as meaningful to McKinley as it used to be then that's a result of McKinley accepting that the game isn't winnable, not because of conference play mattering more, expanded playoffs or anything else. If McK no longer thinks that they can beat Massillon, then they may as well drop the game from the schedule.
But, I think the fact that a 5-5 Pups team was within 10 points of a Massillon team that is top 5 in the state, on the road no less, shows that the McKinley players and coaches still circle that game on the calendar every year.