It’s better this way, Law and Kidd solidified themselves as Luffy’s rivals again. Makes for a more interesting world where other characters aren’t just Luffy’s supporting cast, and other characters aside from SHs actually have impact. Luffy already won back in WCI if you ask me where everything went the SH’s way.
Making Luffy defeat her after Kaido would be pointless. She’s basically Kaido girl version, and no tension would be left if Luffy already on her level the next time they fight. Now the new generation plotline Oda wants is relevant again, and chaos in the world will officially start after Wano