Since the USA designs most of the software in the world, support for changing time zones will gradually disappear.
There will no longer be a constant force making people correctly convert UTC to localtime. People will go storing dates as strings. People will just have "+8 hours" hardcoded for their application.
That will lead to people in the rest of the world having constant bugs and trouble every time daylight savings time happens.
That may be part of the push for other countries to drop it too, when lawmakers see that every spring and autumn their computer deletes an hours worth of emails or their fancy web 4.0 microwave cooks their breakfast for 1 hour and 30 seconds.
