Then feel free to give your examples. I'm not gonna cherrypick here, but do you really think that the 10 cacoward winners in 2019 were all better than Sigil? Other than Eviternity, all of them are now forgotten, and none of them were actually anything remarkable.
Tech Gone Bad won, because back in 2016, it was an all rosy, look who's back moment. When Romero became a competition, suddenly everybody started shitting on him, and using this "your wad is only played because of your name" fake narrative. Granted, if he had made something average, it wouldn't have become popular. Sigil was popular because it was good, and refreshingly different to the typical community wad, didn't follow the tired tropes, and all levels had their own visions and own gameplay/visual narratives.
It doesn't mean Sigil didn't have its issues. Shotgunning barons in the early levels were pretty annoying, the crusher maze in M4 could have been better and the secret level was mediocre. It's a 8/10 wad, yet, it was objectively better than at least 7-8 of the year's cacoward winners.