The Nexus line really saved Android -- it was always the excuse (the best word I can think of) when other devices had update, performance, or security issues. "Well it isn't Android, it's Samsung/HTC/Motorola/Sony/etc, because my Nexus...". It was a critical line.
Google may have killed the Nexus line by making the 9 and 6 so uncompelling, but I doubt it was intentional. They're just a company that has a chronic difficulty prioritizing customer service. Further I don't really think it's "high expectations" to demand that voice functionality works (again, this stuff gets you in serious trouble with regulators. If this were raised to the FTC and/or CRTC, you can bet Google would find a fix extremely quickly).