[DamonHD]

Have you explicitly told your phone etc to ignore sync or to use network time? My consumer stuff all works fine (Android and macOS), so I don't that think your sweeping claim in the headline is true. You may have simply gave a few troublesome devices with bugs or inappropriate settings/overrides.

(Yes, I care - I have run NTP servers including some of the first in banking - since long before it was fashionable, and some of my code is probably still in ntpd.)

[Last5Digits]

While I apologize for making general claims without a significantly larger sample size, I have tried this on all of my devices and those of family and friends. I only have access to phones running Android and laptops/desktops running Windows, so I cannot say whether macOS/iOS and Linux suffer from the same issue. I'm looking at ~12 devices from various manufacturers that all have similar amounts of clock drift.

All of the devices have network sync enabled, and they sync to accurate time if I manually disable and enable it again. The issue is that they don't sync regularly enough by themselves.