It all depends on how those MMOs pan out. I remember when rift, swtor, gw2, tera, Wildstar++ launched about 6-10 years ago. Right when those games released alot of people flocked to them and played it. It continued for a while and all of those games "died" off. Most are still going, some are completly shut down.
We gotta remember that theres no other mmo out there with such a huge playerbase that has such a strong connection to the game. Many of us has played the game more or less for 15+ years. We might get distracted by other games now and then, but we always return to wow.
So when it comes to these new MMOs coming out we gotta ask ourself: Will they be games that hooks us right in as wow did/does? Will it be MMOs that makes millions of players outright addicted and sucked in for years as wow did/does?
I have little to no faith in New World as a long lived and highly popular MMO. I'll play it at launch and have fun with it, but I doubt it will last.
AOC is to far off to judge now. But so far, it doesnt give me the "this is it" feeling.
The MMORPG that Riot is making might be awesome, cause at this point we know nothing at all.
People are looking for that next big thing that captures them like wow. People just dont want a good MMO, they want a god damn behemoth of a MMORPG worthy of ruining your personal life for.
For all we know 9.1 might be great, 9.2 might be great and 10.0 might be god damn epic. wow might be in a rot right now, but it can quickly turn around.
People will get distracted by other MMOs, but I doubt the masses will be captured by a new MMORPG in the coming years that wow managed to do. People will play the MMOs, but they will probably for the most part quit the genre or go back to wow. Personally im going to check out most mmos coming out, but I highly doubt it will be long lived.
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A very important point. For many its either wow the MMORPG or no MMORPG at all.