It's not a valid point of argument. 5+ years ago, Riot revealed Dragonmaster Swain, claimed it would even be coming out soon. Not too long after that, they said "Oops, we fucked up, we couldn't make it how we wanted, it's dead now." This was after the hype of all the Swain mains that they'd be getting a kick ass skin. Riot over those 5+ years has been on and off again about the skin, perpetuating it in death, but always hinting that it might return given the right circumstances.
Then Swain gets his VGU, and the right circumstances come up - here they had a team ALREADY working on Swain and remaking his skins, so why not have them slip in this other skin that Riot has been talking about for over 5 years? This is an exceptional circumstance, a design that had already been discussed and fleshed out by not just Riot, but also the community for YEARS. Here they had a team devoted to rebuilding Swain and his skins, and here they had a skin design that was pretty much already done and coveted by the fans. That was why they made and released this skin, because it had been concepted and promised years ago, they had supremely disappointed the fans because they canceled an already announced skin, and here was the opportunity to make good on that promise.
Irelia never had any skins that were promised and then cancelled. Neither did Urgot, Galio, nor Evelynn. Swain was THE ONLY champion to have this happen to him and it was a huge PR bungle for Riot. That's why Dragonmaster Swain is an exception, because it is their way of correcting this PR bungle and pleasing the fans who for years have been begging for this skin to finally release.
It doesn't belong in this argument because this skin has history and is a special case. It's not just some regular skin that's part of the normal skin production cycles like Pool Party Taric was or Birdio.