And my defense of Yoko falls under the category of "we just don't know". Maybe John's contributions would have been terrible without Yoko in his life. Maybe he would have given up on the band completely. Maybe he would have written ever better songs and been the creative driving force to keep the band going until 1974. Who knows...?
It's just one of the endless alternate timelines to ponder. But the one we got, where John & Yoko were together and we got the albums and solo work, satisfies me.