There is another consideration worth bringing up.
In the past, players have complained that vintage had become a format where there are no meaningful decisions to be made after the sideboarding and mulligan phases of the game.
From what I've seen, it appears that Lurrus leads to increased interactivity, and leads to the better player winning more often.
For instance, in this video, Andrea Mengucci says that he achieved an overall record of 33-3 with a Lurrus deck, facing a lot of other Lurrus, and that the games are very "grindy", with many games finishing due to a player running out of time due to the sheer weight of so many difficult decision points. Lsv tweets here that he went 8-1 in a challenge with the same deck, mostly facing Lurrus.
One could reasonably hold the opinion that the pro of increased interactivity/gameplay-skill outweighs the con of decreased deck diversity. Perhaps future companion printings can increase diversity and we can get the best of both worlds.