It might be the start of the end for air.
It already started with AMD recommendation for 240/280AIO on 7900X/7950X. Moving forward to ZEN5 you might see even smaller die so even lower tier will need water to stay cool (or with decent frequency..)
The top preforming air coolers will stay, as they can mech or outperform even mid-level (good 240/280) AIO. The rest will gradually go away just as personal cameras (non DLSR) almost completely disappear as smartphone emerge. For small, low end (i3\R3), office computers air will stay of course as it is so much cheaper, just as you can find many basic cameras in car dashboard, home security\surveillance and such.