Do you encounter people using UTC regularly? While it's the closest we have to a world timezone, in my experience people don't use it much outside of a technical context.
I usually see Americans treat Eastern Time as a standard, with references to Pacific sometimes. In the EU, where I am, CET is the usual timezone used for specifying a time internationally. And regardless of the location, it's very common for people to specify a time in their local timezone first and leave it to the other party to figure out what the difference is.
I haven't encountered situations like someone saying "let's have a discussion at 16:00 UTC" to set up an EU-US meeting.
My colleagues and I do this, but we're often involving 3, 4, 5+ timezones. Everyone knows their own offset from UTC, but I easily forgot whether Australia is on DST this month.
I agree to an extent, but I don't really see the problem either. If I book a meeting or something through any calendar application, the timezone will be fixed to the local timezone. Let's say I book it for 13:00 in my calendar, it will show up as a meeting at 14:00 in their calendar if they are +1 from me.
So whenever I specify a time with someone that could be in a different timezone, I would either make sure that I am using some application that solves it for me, or I would AT LEAST include the timezone.
Maybe I'm just not encountering the same problems that you do.
I usually see Americans treat Eastern Time as a standard, with references to Pacific sometimes. In the EU, where I am, CET is the usual timezone used for specifying a time internationally. And regardless of the location, it's very common for people to specify a time in their local timezone first and leave it to the other party to figure out what the difference is.
I haven't encountered situations like someone saying "let's have a discussion at 16:00 UTC" to set up an EU-US meeting.