***DISCLAIMER RIGHT OUT DA GATE
I'm gonna go all preachy and be incredible decisive with my reaction. This is in no offense to try and harm people for their own opinions because I may or may not have missed something, but this is entirely based off of data that I personally got. Your experience is different from mine and I fully respect that. Onto the verdict.
Oh boy.
Y'all put some pretty clean arguments up i'll admit. Thing is though with as much talk about team building and making a team to counter a play style, the same could be said towards any prankster really. Even I, speaking as someone who remark'd on how powerful a full SwagPlay team is. No real sane person would dare ladder with a SwagPlay team. The tactic is highly averaged on a coin flip of 50%/50%.
This doesn't mean it gets a free-pass. When you usually see Klefki and Sableye or even other popular prankster users such as Liepard and Whimsicott in a line up either by themselves or together, they usually have someone covering their weakness. There is also some issues with some of the things that Kyra said were Checks or Counters towards SwagPlay. I'll list of some reasons why based on research from playing matches on Showdown, Reborn, and PO Main.
As you can see, not a lot of options really stick out except Mandibuzz. Even if Mandibuzz does get a lot more usage people will gradually shift over to things like Landorus-T, Kyurem-B, or Excadrill to counter Mandibuzz. You gotta understand that if something becomes popular, people will try to find ways to remove it. At the same time when a removal effect proves effective, resistance will grow back.