Would a Raid Only MMO Work?

Would anyone here consider playing an MMO that only focused on Raid progression?

There would be the chance to make really difficult encounters that take ages to do but drop an absolute ton of loot so you don't feel like you are farming.
I think without being forced to focus on open world aspects a dev team could work on making lots of cool boss mechanics and really complex talent and gear choices.

I'm sure it would come down to how exactly the system gets monetized because for an MMO to work people need to play a lot so there is always someone looking for a group which is generally why WoW and other games have busy work.
eg. when you are bored so you level an alt but then you see a group looking for your main class and you ping them to join. Whereas without leveling you might have just stopped playing to go do something else and not seen that group request.

That is the argument against a raid only MMO, but on the other hand you could argue that online communities who might not have a big active play time might still want to log in for raid night every week and it might be more popular because of the lower commitment.

I know there are some games that do this right now, but Phantasy Star Online 2 and Monster Hunter both have very low player caps for instances. I'm talking about 20-40 players taking down a boss, not 2-5 players.

Is this practical, would you play something with no open world?

I'm assuming that the structure you have in mind is something like a main lobby room and then you go straight into instances, get loot, return to lobby and so on?

I think it'd be a bit harder to delve deeper into the worldbuilding aspect of things, which means that the world/story structure would have to be different than what we have in say WoW. Then again, this kind of game design would naturally lean towards gameplay over story as a selling point anyway so there's also that. Nevertheless, for me personally half the fun is raid is the context/role, so it might also affect some players in some way (would you be as interested in Icecrown Citadel without Arthas's lore?).

I think the biggest factor though is how the reduced social and story aspects would be able to support a raiding environment; as we all know, maintaining a raiding-capable guild is a lot of work, and a part of difficulty in progression comes from social loyalty, among other things, i.e. how you ensure these 20-40 people to be willing to show up at a certain time and stay for, say, 2-3 hours. This is probably why most modern games have lower player caps, as it's much easier to organize 5 people than 25.

Well, the topic's still very vague so there's a lot of what-ifs, but tl;dr I think it's possible, but also that in order to work the model would need to be much different from what WoW has, which makes it impossible to tell whether it'd work until someone actually tries it.

Start dropping any suggestions, god knows some of us are bored of WotLK