Nice job! You even had so many pokemon weak to SB in the team.
It's also about just having time to accumulate resources besides powercreep. All of those pokemon except Rayquaza existed during Zam's first run and you could have put that team together (swapping Dragonite for Ray) if you'd worked hard for it. I would have been hard pressed to U6 any Zam moveset then, now I have every viable counter to it except Absol maxed.