You can just set your servers to UTC. Although if you're not in europe correlating to local time is a bit of a pain.

why cant we adopt the same standard (along with metric)

There's "Swatch Internet Time" (.beats), they're a form of metric time :)

Nothing prevents Icelanders from getting up at the time that maximises sunlight for them.

The sun does, to an extent: at the height of summer it never sets and at the low of winter it never rises (kinda, technically in Akureyri you do get 3h of daylight or half an hour of twilight at worst, and Reykjavik has a more forgiving 4h of daylight and 3 hours of twilight, no actual night from early april to early september tho)