The following changes take effect on Magic Online on July 25:
Rules change: You may only have one commander. Creatures with a partner ability function as if they did not have that ability.
This was a banned list that Wizards themselves maintained. Paper 1v1 Commander addressed the problem of Partners and Commanders through a different mechanism, which is also practical and hasn't negatively effected those communities. I'm sure people are happier being able to play their Barals in some fashion even though they can't play them as a Commander. (And naturally, kitchen table and player-run events can adopt whatever rules sets they want).
Arguing that Wizards needs to abide by some set principle seems detrimental to the growth of the game. If Wizards is going to be innovative with these types of effects, tournament rules (i.e. banned/restricted lists) should be adaptable as well.
Counter arguments that one instance of "power-level" errata will lead to a never-ending sequence power-level errata is close to a slippery slope fallacy. For one, the inability to deal with a card by power-level banning is unique to Vintage (obviously, cards are supposed to be restricted for power-level reasons which is impractical in this case). Every other format has that ability. Two, even Lurrus isn't dominant in every format. Standard is, I believe, dominated by Yorion decks, which generate obscene value in Fires control shells, blinking Teferi, Narset, and all the absurd planeswalkers, not to mention Fires of Invention, which unlocks your mana and lets you cast more than two spells in a turn. Lurrus is still very good, but not as dominant as it is in Vintage, Legacy, and possibly Modern. Pure power-errata as a response to one or several formats can have unintended consequences in other formats and doesn't work as well in a complex game such as Magic. Online games are simpler. I imagine Wizards would be quite hesitant to implement power-errata as most people envision it, again. The game has simply grown too much.