I don't know who would consider Pixels to be flagships. Other than the relatively pure Android and timely updates, and the relatively good hardware, there are better phones available.

Google is also very strict with their update policy, which means that after 3 years after release, the phone is EOL. I'm repeating myself on here but Nokia (HMD Global) is actually still providing my Nokia 6 from January 2017 with updates every 3 months. I recently went on a research mission for a new Android phone but noticed how bad the situation on Android still is.