If the team wants to have the Emergency QB3 option, they must follow those rules, which state that QB1 and QB2 must be on the 53 man roster and game-day active, and Emergency QB3 must be on the 53 man roster and a game day inactive. If the Patriots don’t want to designate an Emergency QB3, then the old rules apply - meaning a QB2, QB3, QB4, etc. can be either on the 53 or a PS game day elevation, and must be game day active if they want to be allowed to participate in that day’s game. Just like in the past.
The point is that in the past, some teams would have 2 QBs active on game day instead of 3 to save one of those game day roster spots. Teams that choose to do that now (meaning only having 2 QBs active ok the game day roster) are given the option to have an emergency inactive QB3 but only if they follow the specified rules. Teams can still just choose to have all 3 QBs active game day active as in the past, but it seems silly when you can have a freebie inactive QB3 instead. But the Patriots current QB setup won’t allow that since the new rule requires all 3 QBs to be on the 53 for it to be an option.