This signals to me that Google thinks that Chrome either has, or will soon have, a significant enough market share where it is realistic and useful to move their invasive tracking methodology from the web into the browser. Maybe they also realize that any sensible browser vendor which is not also an ad giant should already be blocking web-based tracking technologies. So why even try to make them compatible.
Honestly, as long as Firefox is still compatible with most sites, this won't hugely impact me. After that, I don't know.