I think his point was that if CPC decreases monotonically forever, then eventually revenue will have to suffer regardless of volume growth. As others have menti

I think his point was that if CPC decreases monotonically forever, then eventually revenue will have to suffer regardless of volume growth. As others have mentioned, this doesn't take into account the mix of new ecosystems, though it's noteworthy that Google doesn't break down CPC by segment so we could see trends for desktop/mobile/YouTube/etc/