Extended support is very difficult to provide in a way that fits into the expectations we have for robustness, app compatibility and security beyond the lack of incomplete patches. For example, it would be easiest for us to move the Pixel 4a (5G) and Pixel 5 to Android 14 QPR2 to avoid having a separate legacy Android 14 QPR1 branch where we need to apply backported AOSP patches which sometimes don't apply cleanly. However, the Pixel 4a (5G) and Pixel 5 do not officially supported Android 14 QPR2 but yet had a bunch of changes related to it done to their repositories. We also build the vendor image ourselves rather than using a prebuilt one, so it always gets built with the latest SELinux policies, HALs, etc. available in AOSP. Quarterly releases are now trunk-based so it's similar to the major yearly releases. Moving Pixel 4a (5G) and Pixel 5 to Android 14 QPR2 is entirely possible. We could revert the QPR2 changes for them and use a QPR1 vendor build. The issue is that we know there are going to be regressions, and we do not want to ship dozens of serious bugs to users which we then have to invest substantial time in resolving. It's all time taken away from our focus on privacy features, security features, trying to have perfect app compatibility beyond apps forbidding using a non-Google-certified OS, etc.
We're very happy that support increased to 5 years for 6th generation devices and then 7 years for 8th generation devices because we will no longer feel the need to do harm reduction via extended support. It will save us a huge amount of time and concern about people continuing to use these insecure devices.
7 years for a phone that's used as a main personal phone is a long time. Most people aren't going to use it that long, particularly a flagship phone. It mostly benefits people buying it used. It would be quite strange to buy a Pixel 8 Pro and use it for all 7 years. The audience for using a phone that long is probably going to buy a cheaper phone. The main benefit is to someone buying a used device where it still has 4 years of support after someone replaces it after 3 years. We aren't a fan of people unable to afford new phones getting insecure used devices. This is a big step towards that not happening anymore. 7 years is longer than iPhones have been getting full support updating them to the new major OS releases with full security patches.
We worry a lot that we're encouraging people to keep using insecure devices by providing extended support but we feel we have to provide it with how many people are clearly still using the end-of-life devices. However, how much of the amount of people still using them is because they think they are fine due to continued GrapheneOS support? This bothers us.