Bisharp rose to OU around the time Spectrier got banned. This Acherus Deathcharger may have gotten the banhammer but Dragapult did not and this period in SS OU's story was one where several users were clamming for a Dragapult ban because no Tyranitar pursuit means Dragapult happy. Anything that could temporarily stave off Dragapult was welcome and Bisharp was one of those things. It actually rose around the same time as Weavile but Bisharp distinguished itself with its ability to threaten Clefable with instant death. It's ability to take advantage of Landorus' intimidate was also welcome because it was a free choice band
Bisharp was mostly the same as Weavile. Knock stuff off and threaten to kill via sucker punch. However, over time, Bisharp fell off, hard. Not immediately but slowly. Relying on sucker punch for priority is not reliable at all and it's slow as for an offensive Pokemon. More and more trends started slapping Bisharp's ass hard as it dropped. Choice scarf Tapu Lele, Urshifu, and Buzzwall to name a few. Above all was it was in direct competition with Weavile, whose speed tier provided natural speed control and it can threaten both Dragapult and Garchomp with instant death without having to do some coinflips via ice shard. It was also in competition with galarian Zapdos for a defiant user and Zapdos had a much more useful ground immunity and a switch move in uturn. Galarian Zapdos even paired well with Regileki to force Landorus to come in and take advantage of the intimidate and since Zapdos is faster, there was no need for that coinflip with sucker punch. Of course, galarian Zapdos itself fell as well when its regular form return
Later in the generation, it also didn't help that Tyranitar returned with a vengeance with its very strong choice band set that took advantage of Landorus focusing on special defense thus allowing it to spam crunch and stone miss more easily. Since it rose to OU, I don't think Bisharp's ever dropped to the lower tiers again. But it really sucks right now which is why it is at B- in the vr
