The Galactic Standard Calendar was established in S3 of Mando when they mentioned Taungsdays. Interplanetary commerce and travel would essentially require a standardized time and date system as well. The simplest answer is that Mr. Krabs just wrote a clunky speech.

Four score and seventy solar rotations ago, on this planetary rotation...

They are hesitant to talk timelines because the Disney products played fast and loose with them.

I think that's a fair argument though I would expect a civilization that advanced and widespread to have adopted standard measures of time. Which I previously would have assumed a "year" to mean something like a full solar orbit of coruscant. There's no reason for there not to be multiple standards, though, but it would be nice if that's what they were going for they didn't just say "year".

Okay but then it makes no sense to mention "this day" either. They should just say "some time ago we did that thing".

At this point, you kinda just gotta accept that the galaxy in Star Wars just has an extremely short memory.

Jedi are legendary warrior-monks/peacekeepers/whatever in the prequels, but then 19 years later someone who was already alive during those times (Han Solo) claims to have been all over the galaxy and never heard of no Force.

That's like, idk, someone born in the 90s not knowing about 9/11

If he had just said "several years ago" I'd get it. That's a massive political shift that didn't happen overnight, Battle Endor may have been the fall of the empire, but the Empire still existed. It took time for the New Republic to form and then wrest control.

In the same way that Rome didn't disappear overnight.

But because he said "on this day" it means this planet/sector has chosen a specific date, which would include a year.

It's by far the best Disney SW show. And it's not lazy writing to stop pandering to uhm akshually types, avoiding dates is important because allows the show to be in universe but not mired in it.

Looks like you're right. Full speech:

On this day several years ago, the Empire was defeated thanks to the heroic efforts of Commander Ezra Bridger, who sacrificed himself to liberate our world.
This monument we dedicate here today stands in recognition of Commander Bridger and the rebel leaders who fought so valiantly on our behalf.
May their courage and commitment never be forgotten.

They're still commemorating a widely known and admittedly recent culturally dynamic event... The damn plaque likely has the fuckin' hour on it, FFS, but he still chose to go with "several years ago"? 🤦🏼‍♂️ I've watched this episode the times now (hoping to get two friends into the series, separately), and it didn't get any easier to explain. Just sloppy. 😬

Yeah I thought the same. They're talking specifically about the event that happened on Lothal. Still not sure why they didn't just say a specific number instead of just "a few years ago" but that was my understanding.