That’s all good info and explains some of the problems that could be resolved for us programmers if we were on UTC, but for the most part these are programmer problems and the computer handles it for everyone else. Additionally, it makes a few issues clear that won’t be resolved with a UTC switch.
First, as mentioned countries all over the world decide for themselves what timezone they’re going to follow. Even if countries were to switch to UTC, we know they all won’t do it nor at the same time, so programmers will have to deal with that added complexity too having some on UTC, some off, some switching on this date or that… if the movement got serious we’d have another Y2K frenzy, but not one that ended on a specific date… it’d linger for years as various countries came on-board. Additionally, we’d still have to deal with all the historical calendar, timezone and DST switches he mentioned. Those wouldn’t go away… in fact we’d be introducing a bunch of new ones.
Fact is timezones are understandable and work pretty good for normal people and their day-to-day tasks. Normal people aren’t going to want to understand UTC and then have to translate their normal day times to and from others around the world. No matter where you are I understand what you mean when you say your morning started at 6am or you eat at noon or you go to bed at 11pm or 23:00 for that matter. With UTC I don’t know what 23:00 means in Australia, Germany or India relative to your day… not only programmers but even normal people would have to know how to translate that to a time they can relate too, so you’d have to know timezones anyway. So while I’d know 23:00 was exactly the same point in time for each of us, I wouldn’t know how it relates to your day the way it relates to mine… is it morning, night, mid-day? It would actually make today’s programmers problems - which isn’t too common for most of us - a problem for everyone.