Harvest Moon started that as far as I know, came out in 96/97, though it was more of an RPG with farming as the core gameplay loop rather than just a farming sim.
I meant more the "simulator" games like Train Driver Simulator, Truck Driver Simulator, etc. that only really took off in the last decade (AFAIK).
But certainly Harvest Moon has been a genre that's now entered the western mainstream much more, and took a while to 'take off' in the western markets with things like Stardew Valley and Animal Crossing in recent years.
The mundane simulator genre did exist in Germany way back in the 80s/90s, I remember a nice airline simulator I bought on a trip there (I'm from Sweden).
As a kid in the 80s I was obsessed with a C64 shareware game called Agricola. You owned a farm and could buy and sell farm land, forest and farm animals. Probably the most exciting part was that you could also race horses (or rather watch them race and place bets). Never thought about it before as a mundane farming simulator. And yet it mostly was a mundane farming spreadsheet.
Fun fact about "Harvest Moon": the western publisher lost the contract to localize the original series, but still commissions new games under the same name. Remakes of the original series are localized by a different publisher under the name "Story of Seasons". It's a little bit like the Guitar Hero vs. Rock Band saga.
