And here's the only flaw I see in your post.
Because it's not BASICALLY the same as having multiple GMs. It's a table filled with GMs, all vested in the game world, all dedicated to make the play experience good for EVERYONE, not just their own personal glory of finding the magical broom of Iuz.
Which means, nobody gets their own personal glory. Is that a net win? I have no objections to shared storytelling experiences. I've played in some. However, it is a distinctly different style from the traditional RPG, and also requires recruiting multiple GMs. I don't know what everyone else's experience is, but usually it's an accomplishment to recruit just one.

But clearly, if you like being a player, or if you like being a GM who facillitates players, the "all GMs" game is going to miss in some ways.
It is certainly possible for everyone to play meta, but it detracts from the immersion. A dedicated GM has a big advantage in creating immersive play, in that the GM has responsibility for most of the meta stuff. In effect, "the world" is the GM's character and there is no role confusion. Whereas in the all GM game, each player must either juggle between meta, GM stuff and immersive play, or give up on immersion in a character. If everyone is the GM, if all characters are effectively NPCs, then the game becomes a matter of shoulds rather than I-wills. It makes sense for this, wouldn't it be cool if, etc., versus, "I attack the guard."
The traditional GM gives up attachment to individual characters, but what they get in return is the opportunity to orchestrate events and interactions. They have great narrative power. If you run a multiple GM game, no one GM has authorial control. I can invest motivation in the evil lieutenant if I know what he's for; it is harder to invest when I know another player might narrate him in an entirely different direction. There is a difference between narrative uncertainy and actual ignorance. In the multiple GMs scenario, illusionism is virtually impossible. There is absolutely no way of knowing where a narrative thread could lead.
So the no-GM, all-GM game can certainly work. Just like how you can have a band without a conductor, or a string quartet without a lead player. But in that case, every person must not every contribute to the leadership but accept outcomes of it. It is possible to take a working four person GMless game and wreck it simply by adding a fifth person who is not a good GM. It is possible for the game to stop working because the GMs start seeing different artistic ends.
But most importantly, in the multiple GM game, nothing can be delegated. That may sound contradictory, but it is both true and important. I cannot simply dictate a challenge, check, or other game mechanic. I cannot even state what mechanic will be used. Anything could be overridden or modified. I cannot ask the player, "What would you like to happen?" Instead, I can only invite my fellow player to do as they wished to do anyway. I cannot point to a book or a campaign plan or anything and say, "This is our campaign bible." I cannot let the dice decide.
So, apart from the impracticality of finding so many talented people and grouping them together into one group, and convincing them of the interest of a GMless game, you face an obstacle which I consider significant. There is no one to play the role of cold, hard, inarguable reality. Instead, you have mutiple realities competing for salience, evidence, and regard.
Taken to its natural end, it is not a roleplaying game at all, but a narrative game. No roles, no role-playing.