OP's real question was does cassette cog wear increase chain wear. When chains wear, the distance between any two rollers with the chain under tension increases. The wear on a cassette does not work the same way. As the cassette wears, the teeth effectively get narrower, but the distance from tooth trailing edge to tooth trailing edge doesn't really change. The change in tooth profile may cause the chain to ride higher on the teeth, but it's not obvious that would have any significant effect on chain wear.