Hasn't Camelot Unchained essentially become the developer trying to make a game engine instead of a game? Any "game" that comes out of it will end up just so they can demonstrate the engine, net code, ect. to sell to other companies. I may be wrong but it seems like that has been their main focus and all that there is to see after eight(?) years since their Kickstarter.
In their defense, there's basically no game engine that's not behind a restrictive license as of writing that can be used for a game of that scale.
So naturally, a product like their engine would be more valuable than an actual game. But it would also open up a 'game of that scale' for other companies, indie or not.
Yes, games like EQ were made with less. EQ2's content was made in under a year according to interviews with Hartsman. They basically had an entire engine and platform under development for many years and rushed out the content last minute. But the game does function, and they have an engine, albeit a poor one in modern terms. As the engine was made for EQ2's success, not for 'x game' down the road.
If you have an established 'rendering / gameplay engine', and more importantly, a backend that is proven to work at the scale you are hoping for, you can make any kind of game on that engine / backend. Your costs come mostly from maintaining the engine itself.
Almost every player I talk to wants to see an "MMO in Unreal 4" - the issue with that is there's not really an engine out there that is completely open source and free to use regardless of platform... well, besides Godot, and Godot is too limited in what it can do and does not support mobile or consoles, so it turns off investors and developers who are thinking on a 'bigger scale'. They forget you need a backend of some sorts to handle, store and retrieve player data, including analytics and metrics.
If you go to any investor and pitch a game like Camelot Unchained, you better tell them, "Hey, so I can get this engine that we can sell to other companies, and I need funding for that engine", it is much easier to sell than "Hey, I have an idea for a game based on a concept (RvR) that ultimately failed to achieve major success twice."
Designers, like Mark Jacobs, understands how to pitch a game. He's likely had to pitch games many times over in his career to many VC firms and publishers. Word travels quick in industries, so you need to change your strategy when dealing with them if you are consistently failing to acquire funding.
If you can't give investors a target metric, you can't get funding unless you have some sort of profitable venture.