Well here is why I am going to say your argument is invalid. For starters I'm 41, my friends are much older than you, and had full time jobs and careers in 2004/5. Also anyone who got exalted with any faction during vanilla was not casual in any way.
Not at all, I am stating simple truths. WOW is a behemoth of a game and it has forced the video game industry to change, some things for the better, but for the most part it has ruined the MMO genre forever. I highly doubt you understand what a MMO was about prior to WOW, and what the point of these game were. They where live 24 hour persistent world versions of P&P RPGs like AD&D. They where not based on the concept of "End Game", the point of the games were the game and the leveling experiences. WOW changed that model forever, WOW made the "End Game" the point of a MMO, which is why each expansion they lower the amount of time it takes to level through older content. As a test I level a monk 0-90 in 2 weeks time, and that is with a full time schedule. However the boys at Blizzard still make sure to include a ton of grind in everything we do. How many dailies are there now? The whole concept of dailies is a grind.
But lets look at EQ SWG COH
EQ and SWG are examples of the typical MMO experience from 1999-2005, if your goal was 'end game' you really missed the point of the game. They where about playing with friends and leveling together much like AD&D was about group play. They were not designed to play solo, and to play at max level.
COH which came out 7 months prior to WOW was really the first MMO to have good solo play, you could level 0-50 solo in it. Granted it was designed so it would take 2 years of casual solo play to get max level. However as a part of encouraging group play they had a system for teaming which allowed a high level player to sidekick a low level player, which effectively made them the same level. making it possible to play with anyone and everyone in the game, no matter the level. Also because of the design it was the least grindy MMO in early MMO history, one reason why it was nominated as Game of the year by every magazine and g4. It won a lot of honors, and stayed popular until about 3 years ago when 1/2 of it's players left for Champions Online.