> This "upstream first" approach to product kernel development and testing is extremely efficient. Google has been successfully doing this with Chrome OS and Android for a while now, and is hardly alone in the industry.
This seems to be conflating testing a product against an upstream kernel and making your stable Linux distribution use an upstream kernel. A huge number of open source projects and vendors already do the first thing without any difficulty. I believe that doing the second thing is much rarer. Do Google do both things?