This is definitely something people do, it’s not an outlandish concept. But it comes with major downsides.

The flipside of the single point of failure is that a GM-based game needs only one competent and dedicated person to keep the roleplay functioning. If all the other players are flaky and passive-reactive, it might not be a [i]great[/i] roleplay, but it can continue to function on the shoulders of the GM. Whereas a game with shared control needs multiple competent and dedicated players to work, because one person isn’t going to do the heavy lifting in a story they don’t have any reliable authority over. So you need at least two people who individually would have been competent enough to be GM, or really three to avoid the risk of it devolving into a one-on-one.

On the other hand, with shared control, it only takes one player without a good grasp on plot coherence or setting integrity to ruin it for everyone else. You [i]could[/i] democratically veto someone’s contribution, but the effort to do that is so much higher than when you have one person with the authority to just say no. I’ve been on this site much longer than my account indicates and I’ve seen it plenty of times.
[sub](This doesn’t apply to anyone I'm playing with at the time of writing, don't worry.)[/sub]

Now, I’m not saying you shouldn’t do it. In fact, I think this is the most fun way to play [i]if[/i] you can assemble a group of competent and proactive players. But GM-based games are more resilient to the environment we realistically live in, where the majority of players have good material to contribute but lack the competence, proactivity, or time to actively prop up a plot and setting.