Ask HN: Why are the Android phone apps (Contacts, Messages, etc.) so slow?

I've owned a Pixel 2 and a Motorola something-or-other. On both phones the built-in Android apps were outrageously slow (compared to other apps like Facebook Messenger, Gmail, etc.) Long rendering times when I went into a sub-screen, slow search, major delays with adding multiple names to a single address line, etc.

What gives? Aren't these apps mostly fetching and displaying plain text stored locally--shouldn't they be really fast?