You know, I wonder when we started eroticising and short-stacking goblins. I feel like it started with one of those early 2000's fantasy indy comics, but I'm not sure.
@moximoore If it didn't start with Midna, she SUPER popularized the shortstack aspect for sure.
On a purely fantasy level, they make a good contrast to the tall and lean elf archetype (who was 98% taken by heroic and orcs)
Then you also have the rise of monster/non-human girls as a whole in a lot of niche culture at the time (anime, manga, games, web comics, fan stories, indie games, etc)
All that combined with indie projects that focused on and sexaulized them of the course of the last nearly 2 decades.
@moximoore: I'm not sure, but the first artist I remember having sexy goblin women is InCase, though that was just a handful of years ago. Looking further back, the earliest I can remember shortstack goblins with exaggerated proportions is in Corruptions of Champions. They weren't in there at first, and I don't remember what version added them, but that's the earliest example I'm aware of.
I think the thing that got goblins started, though, wasn't them being shortstacks, but them being aggressively sexual. Goblins are classically rapacious, so female goblins, when they showed up, shared that tendency. That's just my theory of where/why/how they started getting popular.