[Insimwytim]

DST works fine with Unix timestamps.

It's the scheduling changes that disrupt DST switch (or something else) need adjusting to. But this is usually planned in advance and everyone would (or at least should...) update their tzdata.

The amount of issues you'll have due to those (comparatively rare) changes cannot even begin to compare to the amount issues you'll have with datetime stored in timezones.

[mgaunard]

You're suggesting pre-filling future data based on extrapolating current rules (up to an arbitratily unknown high date) instead of using a constant.

I don't really see how that is a good approach in any capacity.