Well said. Anything vivillion can do, other support Pokemon do it better.The VGC viability ranking lists are meant to be a reflection of both how good the Pokemon is and the success of the Pokemon in the irl VGC metagame. Vivi has no success in the metagame - I don't recall ever seeing it in a top cut, and its measly 287 CP total post Incineroar reflects that.
Many viable irl teams are also equipped to handle Vivi without trying to. Vivi fails easily to any two Pokemon faster than it. Teams without two Pokemon faster than it often still have ways to deal with it, for example, slower CHALK teams with only Scard Lando-T outspeeding it still have bulky AV Kartana who can finish it off without caring for Sleep Powder / Rage Powder (and I'd happily let Lando-T sleep if it means KOing a Pokemon - Lando-T can still Intimidate stuff). On that note, in general, a Pokemon isn't worth if it only thing it does is sac itself to sleep something, and that is often what Vivi will at best acheive.
With your replays:
1st one: Your opponent did not have a good team in general. Besides having issues with Vivi, he's weak to fast strong threats in general as he seems to lack speed control on a relatively slow team. He's also way too Lando-T weak.
2nd one. Vivi fainted in order to sleep Snorlax. Didn't change the outcome of the match. On the other hand, if you brought your Cress instead of Vivi, you would have been more prepared for that MBlaz
3rd one. Your opponent forgot about Shield Dust. Also considering that his Zard Y is not max speed, he should have really brought his Scarf Lando-T as a lead. It's good against your team in general and is a fairly safe lead against your team.
Accelgor is commmonly paired with Tapu Lele, holding a Pyschic Seed to activate its Unburden. It is an extremely fast support with useful support moves, including Encore, Acid Spray, Struggle Bug and Final Gambit. You also can't dick it with priority thanks to Psychic Terrain.
There were also just as many Accelgor in top 32 for NA than non-Mega Tyranitar (0).