yes, if you're not training you can play a 9-12 men roster and do well in the regular season, only to lose to a stronger 5-men team in the playoffs
Exactly.
Given the same sum of salaries, a team of 8 players should do better in a game than a team of 5 players.
Until now, the opposite happens.
This is the key of the problem, and it has nothing to do with adding more games to the schedule.