Games get announced so far out now so that studios can make a judgement call, based on public reception, on whether or not to cancel the development.
Maybe to protect the project from internal politics?
Meanwhile Nintendo announced Ocarina of Time remake out November
This is pretty typical for a new blizzard game. For example Diablo 3 and 4 were both announced 4 years prior to release. Not saying it’s good or bad, but it’s not unusual.
I came to say the same - I remember it being an excruciatingly long wait for SC2, which was also apparently over 3 years between announcement and release [0]