You make some very fair points, but I still don't see why you assume that Chansey's Eviolite will be removed at any given time during the match. It's not like you have to stay in to get Knocked Off and I guess my post should have dwelt more on the fact that I think you pretty much need to run something to take Knock Offs on your team, especially if you're using Bulky Offense. My calling Chansey a win condition was pretty much an exaggeration and I'm not saying you should be using to tank physical hits anytime soon. But still having a physically-based mon is no guarantee of victory in the end-game because when it comes down to it, Chansey can take a lot of punishment. For instance:
252 Atk Sheer Force Darmanitan Flare Blitz vs. 252 HP / 252+ Def Eviolite Chansey: 357-421 (50.7 - 59.8%) -- guaranteed 2HKO
A scarf Darmanitan VS Chansey scenario is by no means unlikely and it will kill itself from huge recoil while failling to outdamage Softboiled significantly. Despite you having a point about Sub set-up physical sweepers (and I actually forgot about Superpower Hydregion myself), the utility Chansey brings even to Offensive teams is unparalleled.
Not every mon with knock off is a strong physical attacker that Chansey wouldn't want to stay in on anyway; Tangrowth and Gligar for example are mons that chansey usually doesn't fear much, but both carry Knock Off.
Also, aside from the fact that you specifically choose one of the very few physical attackers that doesn't commonly carry a fighting move and has huge recoil, the problem for stall teams never was scarfed Darmanitan, but LO-Darmanitan:
252+ Atk Life Orb Sheer Force Darmanitan Flare Blitz vs. 252 HP / 252+ Def Eviolite Chansey: 508-601 (72.1 - 85.3%) -- guaranteed 2HKO
He still nearly kills himself in process, but Chansey gets 2HKOed no matter what, and OHKOed with little prior damage.
Imho, while I used Chansey quite some time myself and it seemed decent, even in this metagame, I never had problems beating it; Any physical Attacker with fighting-type attacks(emphasis on attacker; A physically based wall most likely won't be able to do that) can usually dispatch it, if you get to hit it with a stray knock off, even some special attackers will get past it, it very easily gets worn down to the lack of leftovers, taunt shuts it down completely, it's set-up bait and just one Nasty Plot can turn some special attackers from "easily walled" to "getting 2HKOed" ... One of the more funny ways to beat the wish-passing set is to roar chansey out with a mon that isn't considered a threat before it gets a chance to heal itself; If you have hazards up, it probably won't survive the next switch-in.
Anyway, if you want to use Chansey to its full potential, I would combine it with a sturdy mega, like Aggron or Blastoise, to take the Knock-Offs, while chansey can heal them up with Wish. Granbull also makes a good pairing, since it can take both fighting moves and knock-off with ease, though it really dislikes the loss of leftovers and thus is easily worn down.