Catastrophizing maybe a little bit, but this sounds like turning their back on the broader ecosystem to go wander off for good in the 3rd rate sandbox they built themselves. Android has spent years trying to figure out our to have a secondary display, and the only thing they could manage was to mirror the display, almost certainly in sizable part because Android's boutique homebrew display services are so absurdly constrained. Marrying yourself to this boat anchor of a tech stack is the worst possible move ChromeOS could be doing.
Google's Not Invented Here has always been exceedingly high. ChromeOS has been one of the only attempts Google has made to play well with others, to carve some kind of middle path. It's hard to read this as anything but Google giving up & deciding to go it alone.
They should have done the exact opposite. They should have made Android start using ChromeOS. Or just stay the course. Yeah it's costly having parallel efforts, yeah, but holy heck these feel like existential stakes if you get it wrong, and no longer having anything that interoperates with the rest of technology seems like an obviously hideously bad idea, trusting everyone will adopt your stuff seems bad; Microsoft for example has finally dug themselves out of this hole with WSL, but Google already has a very respectable sensible option they seem like they are about to kill.
Also, seems likely Google was lying a month ago when they said ChromeOS on Android was just a demo. This announcement shows it was their battle plan. Just, not to users benefit, not as a "your phone can also...". https://news.ycombinator.com/item?id=40380022 https://www.androidauthority.com/chrome-os-on-android-proof-...
It only took two months since teams were merged for this awful no good way to throw away so much greatness to go public. https://www.tomsguide.com/ai/android-and-pixel-teams-merge-i...