The core game play of WoW was portable to other games. It wasn't.
Whilst I think your point is generally well-made, I wish people would stop repeating this canard.
Nothing about 4E's "core gameplay" resembled WoW's core gameplay particularly. In fact, the closest comparator for 4E's design is tactics RPGs in general. Roles weren't even WoW's "core gameplay" in 2007 - that's historical revisionism. In 2004 through 2007, WoW was still developing and struggling with the concept of roles. When WoW launched, roles in that sense didn't exist - the "holy trinity" of WoW was not Tank, Healer, DPS - it was Warrior, Priest, Mage - they were the core classes that were to form the spearhead of every raid. Everyone else was kind of in a hybrid limbo to a greater or lesser extent - even the other "pure DPS" classes. In practical terms, Druids could perform the same role as Priests, almost - but Blizzard buffed Priests in various ways to try and make this less true in Vanilla. Bears and Prot Pallies were a joke - totally second-rate and non-viable as real tanks. Paladins were also inadequate healers - they couldn't be the "main healer", because they were a hybrid. This was totally intentional - Rob Pardo was part of a movement, in EverQuest, to try and stop "hybrid" classes being as powerful/useful as Warrior, Mage, Priest (which was then also EQ's Holy Trinity). Only towards the end of TBC, so 2008, did Blizzard really relent on this and make all specs capable of fulfilling actual roles - the change to Prot Paladin in late TBC was particularly spectacular, they went from being terrible tanks that couldn't even really tank normal dungeons, let alone heroics or raids, to being pretty masterful ones, absolutely on-par with Warriors.
Further, even if we say inaccurately WoW had the Holy Trinity when 4E was beign developed, and that roles were inspired by it, it's a bad comparator because 4E uses 4 roles - unlike WoW, but very like EverQuest 1 and arguably Final Fantasy XI and Dark Age of Camelot - specifically, Tank, Healer/Buffer, Pure DPS, and CC character. WoW has never, at any point in its existence, had CC as separate from DPS, but 4E was very clear on separating them and the secondary roles classes had in 4E also reflected this.
I think it's fine to say "MMORPG-inspired roles" or the like, but they're a fraction of 4E's gameplay, not the whole of the core (which was very much about AEDU and tactical movement and so on, stuff that's alien to MMORPGs of that era and even mostly is today), and they're explicitly not WoW's take on roles. WoW finally introduced a 4th role in the previous expansion, like 2022, and it wasn't even CC - it was "Support" (which is a combo of buffs and DPS in that vision)!